The 1990 Tursiops truncatus (Common Bottlenose Dolphin)
Mass Die-off in East Matagorda Bay, Texas: New Insight
into a Cold Case
Errol I. Ronje, Heidi R. Whitehead, and Keith D. Mullin
Southeastern Naturalist, Volume 17, Issue 3 (2018): 411–422
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22001188 SOUTHEASTERN NATURALIST 1V7o(3l.) :1471,1 N–4o2. 23
The 1990 Tursiops truncatus (Common Bottlenose Dolphin)
Mass Die-off in East Matagorda Bay, Texas: New Insight
into a Cold Case
Errol I. Ronje1,*, Heidi R. Whitehead2, and Keith D. Mullin1
Abstract - On 20 January 1990, twenty-three Tursiops truncatus (Common Bottlenose
Dolphin) carcasses were found scattered around the interior shoreline of East Matagorda
Bay, TX. Few accounts exist to document the presence of live or dead Common Bottlenose
Dolphins inside the boundaries of East Matagorda Bay before or after the die-off. We conducted
a review of areal data for East Matagorda Bay and the original investigation of the
January 1990 mass die-off. Information we examined included the history of natural and
anthropogenic changes to the area, dolphin stranding records, small-boat visual surveys,
and dolphin dorsal-fin photographic identification. Natural events preceding the discovery
of the dolphin carcasses were likely factors in the mortalities; however, the timing of engineering
projects that modified access points between the bay and the Gulf of Mexico may
be an additional factor that contributed to the cause of this unusual mortality event.
Introduction
In the northern Gulf of Mexico (southern Texas to southern Florida), 344 Tursiops
truncatus (Montagu) (Common Bottlenose Dolphin, hereafter Dolphin) died
in a Gulf of Mexico (GoMx)-wide unusual mortality event (UME) from January
to May 1990 (Litz et al. 2014). Though a definitive cause for the overall UME
was not found, a morbillivirus pathogen may have been a causal factor in the
majority of cases (Litz et al. 2014). An early incident of the UME was a highly
localized die-off in East Matagorda Bay, TX (Fig. 1), for which it is believed
other factors were responsible. On 20 January 1990, twenty-three carcasses of
advanced decomposition were found scattered around the interior shoreline of
East Matagorda Bay, TX. The Dolphin group’s composition represented a demographic
cross-section comprising 11 males (6 adults, 5 juveniles), and 12 females
(7 adults, 4 of whom were pregnant, and 5 juveniles) (Miller 1992). Following the
die-off, Miller (1992) conducted an investigation into possible causal factors that
included unusually cold weather that froze the surface waters of the bay for 2–3 d,
an abnormally low tide that may have restricted the Dolphins’ ability to leave the
bay for warmer waters, and a freeze-related fish kill that likely limited available
prey, resulting in malnutrition for what was presumed to be a resident Dolphin
population (Miller 1992). However, few accounts exist to document the presence
of live or dead Dolphins inside the boundaries of East Matagorda Bay before the
1National Oceanic and Atmospheric Administration, National Marine Fisheries Service,
Southeast Fisheries Science Center, Mississippi Laboratories, Pascagoula, MS. 2Texas
Marine Mammal Stranding Network, Galveston, TX 77551. *Corresponding author -
errol.ronje@gmail.com.
Manuscript Editor: Barbara E. Curry
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die-off, and it is not clear if the Dolphins discovered in January 1990 were longterm
inhabitants of the bay. A review of the sceintific literature indicated that East
Matagorda Bay had not been studied to determine the presence or absence of Dolphins,
but studies have indicated the much larger Matagorda Bay to the southwest
is long-term Dolphin habitat (Barham et al. 1980, Gruber 1981, Lynn and Würsig
2002, Würsig and Lynn 1996). It is possible that East Matagorda Bay did not support
a resident group of Dolphins prior to January 1990, and more information is
needed to evaluate the Dolphin’s historical and current use of the bay. To that end,
we conducted a review of areal data for East Matagorda Bay and the January 1990
Dolphin die-off, including the history of natural and anthropogenic changes to the
area as documented in the literature and in government reports, aerial photography,
and marine-mammal–stranding records. We also conducted small-boat visual
surveys to assess the current presence or absence of Dolphins in and explore the
status of waterway access to East Matagorda Bay.
Field-site Description
Background
The GoMx Texas shoreline measures some 600 km (White and Calnan 1990)
with numerous industrial ports that feature deep-draft channels dredged to allow for
the safe transit of ships between each port and the GoMx. Prominent among these
channels is the Gulf Intracoastal Waterway (GIWW), a dredged commercial-shipping
artery along the GoMx coast of the southeastern US, and in Texas, the GIWW
spans the coast from Brownsville to Sabine Lake (USACE 1992). Other engineered
passes, or “cuts” as the smaller passes are colloquially known, are dredged to improve
seawater exchange with estuarine communities for the benefit of aquaculture
or recreational fishing (e.g., Rollover Pass and Packery Channel, TX; Kraus 2007).
Although there are several different methods of dredging (Todd et al. 2015), the
processes typically involve the mechanical removal of marine aggregate, followed
by a deposition of the dredge spoils in another location. Dolphins inhabit the state’s
bays, estuaries, and coastal waters (Phillips and Rosel 2014) and at times may be
found concentrated in dredged channels or passes (Fertl 1994, Gruber 1981, Henderson
and Würsig 2007, Lynn and Würsig 2002, Maze and Würsig 1999, Moreno
2005, Shane 1980). Dead, sick, or injured Dolphins are sometimes found stranded
on shorelines (Colbert et al. 1999, Hansen 1992, Worthy 1998), prompting a response
from the Texas Marine Mammal Stranding Network (TMMSN).
East Matagorda Bay
East Matagorda Bay (Fig. 1) is a shallow lagoon (average depth ~1 m) of moderate
salinity (20–24 ppt) comprising approximately 155 km2 (Cifuentes et al. 2006,
Craig et al. 1989, Froeschke et al. 2010, Gardner et al. 2006, Kraus and Militello
1999, Palmer et al. 2011). Oriented southwest to northeast along the northerncentral
Texas Coastal Bend, East Matagorda Bay is surrounded by engineered
waterways including the Colorado River Navigation Channel (CRNC), the GIWW,
and a short, narrow channel—Mitchell’s Cut (Gardner et al. 2006, King and Prickett
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1998, USACE 1992, USACE 2017, USGPO 2017). East Matagorda Bay was separated
from Matagorda Bay after a massive log jam was cleared from the Colorado
River mouth near the town of Matagorda in 1929 (Fig. 2; King and Prickett 1998).
The clearing of the log jam resulted in the rapid development of the Colorado River
delta in the 1930s, closing off the eastern section of Matagorda Bay and resulting in
one of the most isolated bodies of water on the Texas GoMx coast in terms of distance
to inlets where seawater exchange can occur (Froeschke et al. 2010, Gardner
et al. 2006, Wadsworth 1966, White and Calnan 1990). Navigational locks—23-m–
wide steel doors spanning the GIWW channel—were constructed during the 1940s
where the Colorado and Brazos rivers meet the GIWW. The locks control sediment
movement and excessive tidal action; they are open on-demand for commercial and
emergency-vessel traffic but are typically restrictive to the passage of recreational
vessels (USACE 2017, USGPO 2017). In the early 1990s, the Bypass Channel was
constructed around the east Colorado River Lock to allow direct transit between
the CRNC and GIWW, but prior to its construction, all GIWW traffic transiting
northeast was routed through the navigational locks at the Colorado River (McCollum
2000). East Matagorda Bay lacks a natural seawater pass directly into the bay,
although a natural ephemeral pass, Brown Cedar Cut, has previously been a conduit
for seawater exchange (Mason and Sorensen 1972, McGowen et al. 1979, Miller
1992, Munro 1965, USFWS 1988).
Figure 1. East Matagorda Bay landmarks, Common Bottlenose Dolphin sightings, and
survey tracks. Surveys were conducted on 30 July 2016 and 27–29 June 2017. Landmarks:
1. Colorado River Navigation Channel jetty-impoundment basin, 2. Colorado River Diversionary
Canal, 3. Gulf Intracoastal Waterway west lock, 4. Gulf Intracoastal Waterway east
lock and Bypass Channel, 5. Old Gulf Cut, 6. Big Boggy Cut, 7. Brown Cedar Cut (closed),
8. Mitchell’s Cut, and 9. McCabe Cut (closed).
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Methods
Data review
Scientific literature. We reviewed literature relevant to the greater Matagorda
Bay system to establish a timeline of major engineering projects and natural events
impacting the waterways near East Matagorda Bay within 10 y prior to the January
1990 East Matagorda Bay die-off and to determine the extent to which GoMx access
points and adjacent waterways were modified (King and Prickett 1998, Stauble
et al. 1994, USACE 1988, USACE 1992). We also examined records from the US
Army Core of Engineers (USACE), specifically all documentation pertaining to the
USACE permit #18399 (a permit granted for the construction of Mitchell’s Cut,
also known as Caney Creek Fork Cut), obtained by a Freedom of Information Act
(FOIA) request to USACE, and aerial photographs obtained by the US Geological
Survey (USGS) National Aerial Photography Program (NAPP) of East Matagorda
Bay collected 10 December 1989.
Records of marine mammal strandings. The TMMSN maintains archives of
all marine-mammal strandings recorded in Texas since its inception in 1980,
and since 1990 has transmitted all stranding data to the NMFS Marine-Mammal
Health and Stranding Response database (MMHSRP). Stranded animals recovered
by the TMMSN are assigned field-identification numbers that identify the region
in which the animal was found. The TMMSN divides the state of Texas into 6
response regions; Matagorda Bay and East Matagorda Bay are included in the
region designated as Port O’Connor (PO). We extracted, and cross-checked for
consistency, stranding records from the TMMSN (1980–2017) and the MMHSRP
(1990–2017) corresponding to the PO region. We plotted all strandings designated
Figure 2. The town of Matagorda and Matagorda Bay in 1915, before the formation of
the Colorado River delta that resulted in East Matagorda Bay as a separate body of water.
Image from NOAA's Office of Coast Survey Historical Map and Chart Collection, http://
historicalcharts.noaa.gov
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as PO in ArcGIS (Esri ArcMap®10.4, Redlands, CA) to quantify the number of
strandings in Matagorda and Calhoun counties and verify the physical locations
described in each stranding record.
Visual surveys
We conducted visual surveys during July 2016 and June 2017 in East Matagorda
Bay, its connecting waterways, and adjacent GoMx waters (Fig. 1). Surveys covered
the central portion of the bay, the interior perimeter (~300–500 m from shore
or as depth allowed), and connecting waterways including Caney Creek, Mitchell’s
Cut, the GIWW, the CRNC and the Bypass Channel, and the Colorado River
Diversionary Canal. We surveyed GoMx waters adjacent to East Matagorda Bay
~500 m from the beach along the length of Matagorda Peninsula during 1 survey.
We modeled the surveys after NMFS Dolphin visual surveys designed to collect
photo-identification (photo-ID) capture–mark–recapture (CMR) data (Melancon et
al. 2011). Photo-ID CMR is a decades-old technique used to collect data for population
analyses that photographically captures the distinct dorsal-fin markings of
individuals in a population of delphinids (Shane 1977, Würsig and Würsig 1977),
yielding data that can be used to support population assessments (Rosel et al. 2011).
Results
Data review
Scientfic literature. Resolutions to the pre-dredging objections from federalgovernment
agencies (e.g., NMFS) and non-governmental organizations concerning
the effects of the construction on terrestrial and marine species were found during
the review of permit application #18399 to the USACE and the subsequent environmental
review for the construction of Mitchell’s Cut; however, Dolphins were
not listed as potentially inhabiting the area (USACE 1988). Based on the literature
review, a timeline of anthropogenic modifications to East Matagorda Bay during
1983–1990 (Fig. 3; Stauble et al. 1994, USACE 1992) indicates that ~9 km to
the northeast of Brown Cedar Cut, another waterway known as McCabe Cut was
mechanically opened in 1983 as a flood-relief measure for the nearby community
of Sargent, located on the banks of Caney Creek, 8 km north of the GIWW. Mc-
Cabe Cut was initially designed with a bottom width of approximately 12 m and
a depth of 0.6 m at mean low tide (USACE 1992); however, it was mechanically
filled in March 1989 to resolve navigational hazards resulting from a cross current
that developed after the cut grew in size due to the erosional effects of the GoMx
(USACE 1988). As an alternative measure to alleviate flooding in Sargent, dredging
operations were completed in May 1989 on Mitchell’s Cut, a 1800-m–long
channel dredged to a depth of 2.4 m, approximately 4 km to the southwest of Mc-
Cabe Cut, closer to East Matagorda Bay (Rosati III et al. 2013, USACE 1988). In
the months leading up to and temporally overlapping with the UME, 2 dredging
projects were conducted in waterways adjacent to the bay. Approximately 135,215
m3 of sediment were removed from the GIWW opposite the former McCabe Cut
and deposited on the GoMx shore at Sargent Beach during GIWW maintenance
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dredging from September 1989 to January 1990 (USACE 1992). While the maintenance
dredging of the GIWW occurred, another dredging operation, undertaken
from September 1989 to March 1990, removed 1,318,038 m3 of sediment from the
jetty-impoundment basin and entrance channel of the CRNC where it meets the
GoMx (King and Prickett 1998). Aerial photographs acquired 10 December 1989
(NAPP 2017) confirm no bypass channel existed to circumvent the east navigational
lock at the Colorado River. The photos indicate that McCabe Cut and Brown
Cedar Cut were closed, and Mitchell’s Cut and the mouth of the CRNC appeared
open, but with apparent silting (breaking water on presumed sedimentation) present
at the opening of both passes. Dredging operations were not visible in the aerial
photos for 10 December 1989.
Marine mammal stranding records. The stranding archives (TMMSN and
MMHSRP) for the state of Texas from 1980 to 2017 indicated that 123 Dolphins
stranded on the interior shores (e.g., excluding GoMx beach strandings) of Matagorda
Bay and its associated waters (e.g., Espiritu Santo Bay) in Matagorda and
Calhoun counties. The East Matagorda Bay die-off of January 1990 was the only
record of dead stranded Dolphins reported in the interior of East Matagorda Bay,
although 2 response cases occurred for live Dolphins in the vicinity. In the first
case, a 264-cm male Dolphin (TMMSN field # PO331) was found stranded alive in
the GIWW near Old Gulf Cut (Fig. 1). In the second case, a live Dolphin (TMMSN
field # PO528) was found swimming and foraging “out-of-habitat” (Rosel and Watts
2007) in a road-side ditch (depth ≤ 0.75 m) parallel to the CRNC near the southwest
corner of East Matagorda Bay on 13 April 2017 (Whitehead and Ronje 2017).
Figure 3. Timeline of events in East Matagorda Bay (EMB) 1983–1990 related to topographical
modifications and Common Bottlenose Dolphin observations referenced in
Miller (1992).
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Visual surveys
Our small-boat surveys consisted of a total of 29.0 survey hours, and, over the
course of 666.0 km surveyed, we observed 7 Dolphin groups (Fig. 1). We saw no
Dolphins inside East Matagorda Bay proper during the surveys but observed them
outside of the bay in the channels of the GIWW and CRNC, as well as in the GoMx.
On 30 July 2016, we observed a single Dolphin foraging behind a trawl vessel on
the GoMx coast along the Matagorda Peninsula, 1 group of ~12 Dolphins near the
mouth of the CRNC in the GoMx, and another single Dolphin ~8 km upstream of
the river mouth in the CRNC. During the 27–29 June 2017 surveys, we observed
a total of 6 individual Dolphins foraging in the CRNC or GIWW (3 presumed
mother/calf pairs), as determined by the photo-ID analysis. During the visual surveys,
we noted few options for Dolphins to enter East Matagorda Bay. Brown Cedar
Cut was closed, and Dolphins traveling in the GIWW from Matagorda Bay or the
Brazos River mouth (~ 30 km northeast of Mitchell’s Cut) would need to contend
with navigational locks. Only 2 opportunities appear currently plausible for Dolphins
attempting to access the GIWW and the bay from the GoMx: the CRNC via
the Bypass Channel, or Mitchell’s Cut. Mitchell’s Cut was considerably turbulent
during some parts of our survey, and silting of the mouth where it meets the GoMx
was evident. Along the northern side of the bay, we observed 2 potential access
points into the bay from the GIWW (Old Gulf Cut and Big Boggy Cut; Fig. 1).
Discussion
Miller (1992) suggested that, during January 1990, Dolphins in East Matagorda
Bay likely encountered a confluence of unfortunate events—an extreme low-tide
event and a hard freeze of the bay, complicated by a fish kill that may have deprived
the dolphins of prey when it was most needed. Tidal fluctuations are known to occasionally
cause otherwise healthy Dolphins to inadvertently strand on mud flats or
marshes (Gunter 1941, Sharp et al. 2016, Wiley et al. 2001). Although the tide was
reported to be unusually low in December 1989 just before and during the freeze,
≥3 Dolphins were seen inside the bay following (possibly attempting to forage)
behind a trawling vessel on 3 January 1990 (Miller 1992). It is not known if the
Dolphins following the trawler were part of the group in the die-off, but if so, a
trawling vessel in the bay may indicate a route of sufficient de pth was available to
exit the bay into the GIWW before they died (e.g., through Big Boggy Cut). One
dead Dolphin (TMMSN field # PO110) reported in Miller (1992) was found outside
of the bay in the GIWW near the entrance of Big Boggy Cut (Fig 1.)
The December 1989 freeze event froze East Matagorda Bay to a thickness of
~5 cm for 2–3 days resulting in an estimated fish kill of 2.7 million fish, the most
significant on the Texas coast during that time (McEachron et al. 1994). However,
previous freezes had occurred in East Matagorda Bay. The most severe freeze in
Texas recorded history occurred 6 y prior, in December 1983, when the water
temperature dropped 15 °C within 10 d and stayed between 0 °C and 5 °C for ~7 d; a
freeze of shorter duration occurred in February 1989 (McEachron et al. 1994). The
Texas Parks and Wildlife Department conducted extensive fish-kill surveys after
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the December 1983 and February 1989 freezes in East Matagorda Bay (McEachron
et al. 1994), but we found no stranding reports corresponding to either event. The
lack of Dolphin-stranding reports from 1983 could be due to the TMMSN having
only been established in 1980; the organization experienced a period of increasing
public awareness after its inception. However, the TMMSN stranding records
indicate government agencies (e.g., US Fish and Wildlife Service) were reporting
strandings to the TMMSN from the Matagorda Bay area as early as 1981, and by
1985 reporting from the public and state agencies state-wide became consistent
(Hansen 1992).
Active dredging work has prompted negative short-term behavioral responses
by marine mammals inhabiting the affected areas (Pirotta et al. 2013), but population
studies of Dolphins along the Texas coast indicate that dredged channels or
passes such as Sabine Pass (Ronje et al. 2017), Bolivar Roads (Mullin et al. 1990),
Galveston Ship Channel (Fertl 1994), San Luis Pass (Henderson and Würsig 2007,
Maze and Würsig 1999), Pass Cavallo (Gruber 1981), and Aransas Pass (Barham et
al. 1980, Shane 1990) are among waters with the highest concentration of Dolphins
in their respective bay systems. Deep passes or canals may act as bottlenecks that
concentrate fish traveling between estuarine and marine habitats; these topographical
features may have characteristics that boost species diversity and create foraging
advantages (Allen et al. 2001, Anderwald et al. 2013, Maze and Würsig 1999,
Shane 1990, Todd et al. 2015, Wilson et al. 1997). If dredged channels are an attractant
for Dolphins, it is possible that Dolphins in nearby coastal waters explored
Mitchell’s Cut after the dredging was completed in May 1989, resulting in access
into East Matagorda Bay where few prior options existed. It is not certain that the
Dolphins in the 1990 die-off were uncommon visitors to the bay before the cut was
dredged, but the few stranding reports before and after the January 1990 Dolphin
die-off and the results of our surveys here suggest East Matagorda Bay may not
be typical habitat for Dolphins. Mitchell’s Cut may no longer serve as a reliable
means for East Matagorda Bay ingress. Aerial photos indicate the mouth of the
cut has a tendency to accumulate silt, and it may not be a consistent access point
for Dolphins, as it is not maintained. In contrast, studies indicate that neighboring
Matagorda Bay supports a Dolphin population in all seasons (Barham et al. 1980,
Gruber 1981, Lynn and Würsig 2002, Würsig and Lynn 1996).
The closure of McCabe Cut (March 1989) and the completion of Mitchell’s Cut
(May 1989) may have been factors in the Dolphin mortality event in East Matagorda
Bay of January 1990. Dolphins in the GoMx may have gained access through
a new opening (Mitchell’s Cut) and encountered inhospitable natural conditions
once inside the bay (freeze, low tide, fish kill). If a Dolphin group inhabiting East
Matagorda Bay had attempted to leave for GoMx waters before the die-off, it is possible
they were discouraged by the closure of their previous access point (McCabe
Cut) and the multiple engineering projects. Given the navigational locks in place
at the Brazos and Colorado rivers, and the lack of a bypass channel around the east
Colorado River Lock during 1989–1990, it seems unlikely that Dolphins were transiting
to or from the GoMx by means of these passages. In the event they were
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2018 Vol. 17, No. 3
doing so, the mouth of the CRNC and the GIWW east of the bay might have been
disturbed by active dredging operations during the winter of 1989–1990. Visual
surveys for dolphins in East Matagorda Bay and its connecting waterways should
be conducted in association with dredging activities to safeguard the dolphins
inhabiting the surrounding area. Our review may be useful as cautionary insight
for future coastal-engineering projects that create new access to waters adjacent to
Dolphin habitat or alter conditions to restrict or eliminate existing access points.
Acknowledgments
This manuscript was improved by helpful comments from an anonymous internal
reviewer (NMFS), J. Reneker (NMFS), and J. Struve (University of Florida). Thanks to
Elizabeth Stratton (NMFS) for assistance in obtaining MMHSRP stranding records and the
TMMSN for assistance with stranding response and data collection. Partial funding was
provided by the SeaWorld and Busch Gardens Conservation Fund. Dolphin photo-ID survey
work was conducted under MMPA Permit No. 14450 issued to the SEFSC by the NMFS
Office of Protected Resources.
Literature Cited
Allen, M.C., A.J. Read, J. Gaudet, and L.S. Sayigh. 2001. Fine-scale habitat selection of
foraging Bottlenose Dolphins, Tursiops truncatus, near Clearwater, Florida. Marine
Ecology Progress Series 222:253–264.
Anderwald, P., A. Brandecker, M. Coleman, C. Collins, H. Denniston, M.D. Haberlin,
M.O. Donovan, R. Pinfield, F. Visser, and L. Walshe. 2013. Displacement responses
of a mysticete, an odontocete, and a phocid seal to construction-related vessel traffic.
Endangered Species Research 21:231–240.
Barham, E.G., J. Sweeney, S. Leatherwood, R. Beggs, and C.L. Barham. 1980. Aerial census
of the Bottlenose Dolphin, Tursiops truncatus, in a region of the Texas coast. Fishery
Bulletin 77:585–595.
Cifuentes, L.A., J.E. Kaldy, and M.C. Guthrie. 2006. Study of East Matagorda Bay productivity:
Final report. Department of Oceanography, Texas A & M University, College
Station, TX. 33 pp.
Colbert, A.A., G. Scott, M. Fulton, E. Wirth, J. Daugomah, P. Key, E. Strozier, and S.
Galloway. 1999. Investigation of unusual mortalities of Bottlenose Dolphins along the
mid-Texas coastal-bay ecosystem during 1992. NOAA Technical Report NMFS 147.
Charleston, SC. 23 pp.
Craig, A., E.N. Powell, R.R. Fay, and J.M. Brooks. 1989. Distribution of Perkinsus marinus
in Gulf Coast oyster populations. Estuaries 12:82–91.
Fertl, D. 1994. Occurrence patterns and behavior of Bottlenose Dolphins (Tursiops truncatus)
in the Galveston Ship Channel, Texas. Texas Journal of Science 46:299–318.
Froeschke, J., G.W. Stunz, and M.L. Wildhaber. 2010. Environmental influences on the
occurrence of coastal sharks in estuarine waters. Marine Ecology Progress Series
407:279–292.
Gardner, W.S., M.J. McCarthy, S. An, D. Sobolev, K.S. Sell, and D. Brock. 2006. Nitrogen
fixation and dissimilatory nitrate-reduction to ammonium (DNRA) support nitrogen
dynamics in Texas estuaries. Limnology and Oceanography 51:558–568.
Gruber, J.A. 1981. Ecology of the Atlantic Bottlenose Dolphin (Tursiops truncatus) in the
Pass Cavallo area of Matagorda Bay, Texas. Texas A&M University, College Station, TX.
Southeastern Naturalist
E.I. Ronje, H.R. Whitehead, and K.D. Mullin
2018 Vol. 17, No. 3
420
Gunter, G. 1941. Death of fishes due to cold on the Texas coast, January 1940. Ecology
22:203–208.
Hansen, L. 1992. Report on investigation of 1990 Gulf of Mexico Bottlenose Dolphin
strandings. MIA-92/93-21. National Oceanic and Atmospheric Administration, National
Marine Fisheries Service, Southeast Fisheries Science Center, Miami, FL. 224 pp.
Henderson, E.E., and B. Würsig. 2007. Behavior patterns of Bottlenose Dolphins in San
Luis Pass, Texas. Gulf of Mexico Science 2:153–161.
King, D.B., and T.L. Prickett. 1998. Mouth of the Colorado River, Texas, monitoring
program, prepared for the US Army Corps of Engineers. Technical Report CHL-98-2.
Vicksburg, MS. 98 pp.
Kraus, N.C. 2007. Coastal inlets of Texas, USA. Pp. 1475–1488, In N.C. Kraus and J.D.
Rosati (Eds.). 6th International Symposium on Coastal Engineering and Science of
Coastal-Sediment Process 13–17 May 2007. New Orleans, LA. 15 pp .
Kraus, N.C., and A. Militello. 1999. Hydraulic study of multiple-inlet system: East Matagorda
Bay, Texas. Journal of Hydraulic Engineering 125:224–232.
Litz, J.A., M. Baran, S. Bowen-Stevens, R. Carmichael, K. Colegrove, L. Garrison, S.E.
Fire, E.M. Fougeres, R. Hardy, and S. Holmes. 2014. Review of historical unusual
mortality events (UMEs) in the Gulf of Mexico (1990–2009): Providing context for
the multi-year northern Gulf of Mexico cetacean UME declared in 2010. Diseases of
Aquatic Organisms 112:161–175.
Lynn, S.K., and B. Würsig. 2002. Summer-movement patterns of Bottlenose Dolphins in a
Texas bay. Gulf of Mexico Science 20 :25–37.
Mason, C., and R.M. Sorensen. 1972. Character and stability of a natural tidal inlet. Pp.
781–800, In American Society of Civil Engineers. 13th International Conference on
Coastal Engineering 10–14 July 1972. Vancouver, BC, Canada. 2678 pp.
Maze, K.S., and B. Würsig. 1999. Bottlenose Dolphins of San Luis Pass, Texas: Occurrence
patterns, site-fidelity, and habitat use. Aquatic Mammals 25:91–104.
McCollum, R. 2000. Navigation study, Colorado Locks, Colorado River, Matagorda, Texas.
ERDC/CHL TR-00-26. Vicksburg, MS: Coastal Hydraulics Laboratory, US Army Engineer
Research and Development Center, prepared for US Army Engineer District,
Galveston, TX. 158 pp.
McEachron, L.W., G.C. Matlock, C. Bryan, P. Unger, T.J. Cody, and J.H. Martin. 1994.
Winter mass-mortality of animals in Texas bays. Northeast Gulf Science 13:121–138.
McGowen, J., J. Byrne, and B.H. Wilkinson. 1979. Geochemistry of bottom sediments:
Matagorda Bay system, Texas. Geological Circular 79-2. University of Texas at Austin
Bureau of Economic Geology, Austin, TX. 68 pp.
Melancon, R., S. Lane, T. Speakman, L. Hart, C. Sinclair, J. Adams, P. Rosel, and L.
Schwacke. 2011. Photo-identification field and laboratory protocols utilizing Finbase
version 2. NOAA Technical Memorandum NMFS-SEFSC-627. US Department Of
Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries
Service. Southeast Fisheries Science Center, Lafayette, LA. 46 pp.
Miller, W.G. 1992. An investigation of Bottlenose Dolphin Tursiops truncatus deaths in
East Matagorda Bay, Texas, January 1990. Fishery Bulletin 90:791–797.
Moreno, M.P.T. 2005. Environmental predictors of Bottlenose Dolphin distribution and
core feeding densities in Galveston Bay, Texas. Ph.D. Dissertation, Texas A&M University
at Galveston, Galveston, TX. 102 pp.
Mullin, K., R. Lohoefener, W. Hoggard, C. Roden, and C. Rogers. 1990. Abundance of
Bottlenose Dolphins, Tursiops truncatus, in the coastal Gulf of Mexico. Northeast Gulf
Science 11(2):113–122. DOI:10.18785/negs.1102.03.
Southeastern Naturalist
421
E.I. Ronje, H.R. Whitehead, and K.D. Mullin
2018 Vol. 17, No. 3
Munro, G.J. 1965. Job report. Study on the effects of the closure of the Brown Cedar Cut:
analysis of populations of sports and commercial fin-fish and of factors which affect
these populations in the coastal bays of Texas. Texas Parks and Wildlife Department,
Austin, TX.
National Aerial Photography Program (NAPP). 2017. US Geological Survey. Available
online at https://lta.cr.usgs.gov/NAPP. Accessed 13 November 2017.
Palmer, T.A., P.A. Montagna, J.B. Pollack, R.D. Kalke, and H.R. DeYoe. 2011. The role of
freshwater inflow in lagoons, rivers, and bays. Hydrobiologia 66 7:49–67.
Phillips, N.M., and P.E. Rosel. 2014. A method for prioritizing research on Common Bottlenose
Dolphin stocks through evaluating threats and data availability: Development and
application to bay, sound, and estuary stocks in Texas. NOAA Technical Memorandum
NMFS-SEFSC-665. National Marine Fisheries Services, Southeast Fisheries Science
Center, Miami, FL. 146 pp.
Pirotta, E., B.E. Laesser, A. Hardaker, N. Riddoch, M. Marcoux, and D. Lusseau. 2013.
Dredging displaces Bottlenose Dolphins from an urbanised foraging patch. Marine Pollution
Bulletin 74:396–402.
Ronje, E.I., H.R. Whitehead, S. Piwetz, K. Barry, C. Sinclair, and K.D. Mullin. 2017.
Seasonal Distribution and Coastal Movements of Common Bottlenose Dolphins in
Bays and Adjacent Coastal Waters Of Texas. Poster. 22nd Biennial Conference on the
Biology of Marine Mammals. 22–28 October 2017, Halifax, NS, Canada. Available
from E.I. Ronje.
Rosati III, J., A.E. Frey, and R.C. Thomas. 2013. Erosion control and environment-restoration
plan development, Matagorda County, Texas. Phase 2. Preliminary design. Coastal
and Hydraulics Lab, Engineer Research and Development Center, Vicksburg MS. 182 pp.
Rosel, P., and H. Watts. 2007. Hurricane impacts on Bottlenose Dolphins in the northern
Gulf of Mexico. Gulf of Mexico Science 25:88.
Rosel, P., K. Mullin, L. Garrison, L. Schwacke, J. Adams, B. Balmer, P. Conn, M. Conroy,
T. Eguchi, A. Gorgone, A. Hohn, M. Mazzoil, C. Schwartz, C. Sinclair, T. Speakman,
K. Urian, N. Vollmer, P. Wade, R. Wells, and E. Zolman. 2011. Photo-identification
capture–mark–recapture techniques for estimating abundance of bay, sound, and estuary
populations of Bottlenose Dolphins along the US east coast and Gulf of Mexico: A
workshop report. NOAA Technical Memorandum NMFS-SEFSC-621. US Department
Of Commerce, National Oceanic and Atmospheric Administration, National Marine
Fisheries Service. Southeast Fisheries Science Center, Lafayette, LA. 30 pp.
Shane, S. 1977. The population biology of the Atlantic Bottlenose Dolphin, Tursiops truncatus,
in the Aransas Pass area of Texas. M.Sc. Thesis. Texas A&M University, College
Station, TX. 257 pp.
Shane, S.H. 1980. Occurrence, movements, and distribution of Bottlenose Dolphin, Tursiops
truncatus, in southern Texas. Fishery Bulletin 78:593–601.
Shane, S.H. 1990. Comparison of Bottlenose Dolphin behavior in Texas and Florida, with a
critique of methods for studying dolphin behavior. Pp. 541–558, In S. Leatherwood and
Reeves, R.R. (Eds.). The Bottlenose Dolphin. Academic Press, San Diego, CA. 653 pp.
Sharp, S.M., C.T. Harry, J.M. Hoppe, K.M. Moore, M.E. Niemeyer, I. Robinson, K.S. Rose,
W.B. Sharp, S. Landry, and J. Richardson. 2016. A comparison of post-release survival
parameters between single- and mass-stranded delphinids from Cape Cod, Massachusetts,
USA. Marine Mammal Science 32:161–180.
Stauble, D.K., J.M. Hubertz, R.J. Hoban, C.R. Livingston, C.E. Pollock, and D.R. Levin.
1994. Coastal Studies in Support of the Sargent Beach, Texas, Erosion-Control Project.
Miscellaneous Paper CERC-94-3. Prepared for the Coastal Engineering Research
Center, US Army Corps of Engineers and US Engineer District, Galveston, TX. 156 pp.
Southeastern Naturalist
E.I. Ronje, H.R. Whitehead, and K.D. Mullin
2018 Vol. 17, No. 3
422
Todd, V.L., I.B. Todd, J.C. Gardiner, E.C. Morrin, N.A. MacPherson, N.A. DiMarzio, and F.
Thomsen. 2015. A review of impacts of marine-dredging activities on marine mammals.
ICES Journal of Marine Science: Journal du Conseil 72:328–340.
US Army Corps of Engineers (USACE). 1988. FOIA Request for Permit No. 18399.
Galveston District, Southwestern Division, Galveston, TX. 357 pp.
USACE. 1992. Gulf Intracoastal Waterway, section 216 study, Sargent Beach, Texas: Feasibility
report and final environmental impact statement. Galveston District, Southwestern
Division, Galveston, TX. 369 pp.
USACE. 2017. What are the Colorado River locks? US Army Corps of Engineers, Galveston
District. Available online at http://www.swg.usace.army.mil/Media/News-Stories/
Article/480377/what-are-the-colorado-river-locks/. Accessed 13 November 2017.
US Fish and Wildlife Service (USFWS). 1988. Studies of the effects of alterations of freshwater
inflows into Matagorda Bay area, Texas and field observations. USFWS Contract
Report No. 14-16-0009-28-066. In USACE Permit Application #18399. 71 pp.
US Government Printing Office (USGPO). 2017.Electronic Code of Federal Regulations.
Title 33. Chapter II. Navigation and Navigable Waters, Part 207, §207.187.
Gulf Intracoastal Waterway, TX: Special floodgate, lock, and navigation regulations.
Available online at https://www.ecfr.gov/cgi-bin/retrieveECFR?gp=1&SID=8eba303
29c10136d6a19942803d65ac7&ty=HTML&h=L&mc=true&n=pt33.3.207&r=PART#
se33.3.207_1187. Accessed 13 November 2017.
Wadsworth, A. 1966. Historical deltation of the Colorado River, Texas. Pp. 99–105, In
M.L. Shirley (Ed.). Deltas in their Geologic Framework. Houston Geological Society,
Houston, TX. 251 pp.
White, W., and T. Calnan. 1990. Sedimentation in fluvial–deltaic wetlands and estuarine
areas Texas Gulf coast: Literature synthesis. Bureau of Economic Geology, University
of Texas at Austin, Austin, TX. 272 pp.
Whitehead, H.R., and E.I. Ronje. 2017. Case reports of out-of-habit marine mammals:
Common Bottlenose Dolphins (Tursiops truncatus) and North Atlantic Right Whales
(Eubalaena glacialis) in the Western Gulf of Mexico. Poster presented at: 22nd Biennial
Conference on the Biology of Marine Mammals. 22–28 October 2017, NS, Canada.
Available from E.I. Ronje.
Wiley, D.N., G. Earlyz, C.A. Mayo, and M.J. Moore. 2001. Rescue and release of massstranded
cetaceans from beaches on Cape Cod, Massachusetts, USA; 1990–1999: A
review of some response actions. Aquatic Mammals 27:162–171.
Wilson, B., P.M. Thompson, and P.S. Hammond. 1997. Habitat use by Bottlenose Dolphins:
Seasonal distribution and stratified-movement patterns in the Moray Firth, Scotland.
Journal of Applied Ecology 34:1365–1374.
Worthy, G.A. 1998. Patterns of Bottlenose Dolphin, Tursiops truncatus, strandings in
Texas. Pp. 47–56, In Roger Zimmerman (Ed.). Characteristics and Causes of Texas Marine
Strandings. Technical Report NMFS 143. Northeast Fisheries Science Center, US
Department of Commerce, NOAA, Woods Hole, MA. 94 pp.
Würsig, B., and S.K. Lynn. 1996. Movements, site fidelity, and respiration patterns of
Bottlenose Dolphins on the central Texas coast. NOAA Technical Memorandum SEFSC
383. US National Marine Fisheries Service. Miami, FL. 128 pp.
Würsig, B., and M. Würsig. 1977. The photographic determination of group size, composition,
and stability of Coastal Porpoises (Tursiops truncatus). Science 198:755–756.