TEXAS COAST ECOSYSTEM HEALTH REPORT CARD
2019
TEXAS COAST: MODERATELY HEALTHY The Texas Coast of the Gulf of Mexico scored a B- overall, indicating moderately good health. Along the entire coastline, ÄZOLYPLZ ^LYL [OL OPNOLZ[ ZJVYPUN PUKPJH[VY KLTVUZ[YH[PUN JVUZPZ[LU[S` OLHS[O` WVW\SH[PVUZ VM [OL PUKPJH[VY ZWLJPLZ KLZWP[L increasing demand from humans. The Texas Gulf Coast also had generally good water quality results, with good dissolved V_`NLU HUK JOSVYVWO`SS JVUJLU[YH[PVUZ <WWLY 3HN\UH 4HKYL KLTVUZ[YH[LK SLZZ OLHS[O` JVUKP[PVUZ K\L [V U\[YPLU[ WVSS\[PVU ^OPSL TPK JVHZ[ LZ[\HYPLZ ZOV^LK H KYVW PU V]LYHSS OLHS[O K\L [V increasing salinity.
)PYKZ HSZV ZJVYLK TVKLYH[LS` JVHZ[ ^PKL KLZWP[L JVU[PU\PUN habitat losses. Oysters and seagrasses were the lowest scoring indicators. For oysters, this result could be attributed to low HI\UKHUJL PU [OL TPK JVHZ[ IH`Z 6`Z[LYZ ^LYL UV[ L_WLJ[LK VY observed in southern waters, due to Laguna Madre’s high salinity. -VY ZLHNYHZZLZ [OPZ ÄUKPUN PZ K\L [V YLJLU[ YLK\JLK JV]LYHNL PU <WWLY 3HN\UH 4HKYL
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Unknown
*Overall indicator scores are based on the region averages.
Bay Health trends Significantly improving Slightly improving
KEY FINDINGS
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UPPER COAST 6`Z[LY WVW\SH[PVUZ PU [OL <WWLY *VHZ[ MLSS ZOHYWS` HM[LY /\YYPJHUL /HY]L` PU ^OLU H Z\KKLU YLSLHZL VM freshwater caused a large mortality event. Seagrasses are extremely rare in this area, due to the region’s relatively low salinity. As one of the more urbanized regions, it is also \UZ\YWYPZPUN [OH[ .HS]LZ[VU )H` L_WLYPLUJLK SVJHSPaLK OPNO JOSVYVWO`SS HUK HU PUJYLHZPUN ZHSPUP[` [YLUK :L]LYHS VM [OL PUKPJH[VY IPYK ZWLJPLZ KLJYLHZLK PU [OL YLNPVU ^OPSL ÄZOLYPLZ ^LYL Z[HISL
MID COAST Oysters and seagrasses in the Mid Coast scored TVKLYH[LS` ^P[O Z[HISL WVW\SH[PVUZ V]LY [PTL +LZWP[L OH]PUN ML^LY \YIHU HS[LYH[PVUZ [OHU [OL <WWLY *VHZ[ [OL YLNPVU OHZ L_WLYPLUJLK IYVHK ZJHSL ZHSPUP[` PUJYLHZLZ HZ ^LSS HZ PUJYLHZLZ PU JOSVYVWO`SS HUK KLJYLHZLZ PU KPZZVS]LK V_`NLU ;OL KH[H VU IPYK WVW\SH[PVUZ ^LYL SPTP[LK ZV [OL ZJVYLZ MVY [OL 4PK *VHZ[ HUK <WWLY Laguna Madre were consolidated. Fisheries indicated V]LYHSS Z[YVUN WVW\SH[PVUZ
UPPER LAGUNA MADRE Due to its natural high salinity, the overall Laguna Madre region has not historically been a good habitat for oysters ^OPJO ^LYL UV[ L_WLJ[LK PU [OL YLNPVU 3HN\UH 4HKYL has, however, historically been a stronghold for seagrasses ^OPJO HYL TVYL [VSLYHU[ VM OPNO ZHSPUP[PLZ +LZWP[L [OPZ WYVSVUNLK WLYPVKZ VM OPNO ZHSPUP[` PU HUK OLH]PS` PTWHJ[LK ZLHNYHZZLZ LZWLJPHSS` THUH[LL NYHZZ PU <WWLY Laguna Madre. The area was also marked by rising DO and JOSVYVWO`SS V]LY [PTL
LOWER LAGUNA MADRE Lower Laguna Madre is notable in its limited urbanization HUK ZLLTLK SLZZ Z\ZJLW[PISL [OHU <WWLY 3HN\UH 4HKYL to high salinity extremes. The region is characterized by OLHS[O` ZLHNYHZZ WVW\SH[PVUZ OLHS[O` KPZZVS]LK V_`NLU HUK JOSVYVWO`SS SL]LSZ HUK Z[HISL VY PUJYLHZPUN IPYK WVW\SH[PVUZ -PZOLYPLZ ZJVYLK ]LY` OPNOS` HS[OV\NO ^L VIZLY]LK H KYVW PU IS\L JYHI HUK ZV\[OLYU ÅV\UKLY WVW\SH[PVUZ PU IV[O <WWLY HUK 3V^LY 3HN\UH 4HKYL
DRIVERS OF GULF HEALTH
FRESHWATER INPUTS DRIVE CHANGE The salinity of coastal waters can have a KYHTH[PJ LɈLJ[ VU [OL ZWLJPLZ WYLZLU[ PU [OL area. Historically, the Texas Gulf Coast has a strong salinity gradient, with low salinity waters PU [OL UVY[OLYU IH`Z MLK I` MYLZO^H[LY PUÅ\_LZ from the land) and high salinity waters in the ZV\[OLYU IH`Z ZLL THW /HIP[H[Z MVY IPYKZ V`Z[LYZ ÄZOLYPLZ HUK ZLHNYHZZ HYL PTWHJ[LK I` MYLZO^H[LY PUÅV^ PU[V [OL .\SM
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:WLJPLZ [OH[ HYL TVYL [VSLYHU[ VM SV^ ZHSPUP[` such as oysters, tend to be concentrated in the UVY[OLYU IH`Z ^OLYLHZ ZWLJPLZ [OH[ HYL [VSLYHU[ of high salinity, such as seagrasses, tend to be concentrated in the southern bays.
Habitat loss along the Texas Gulf Coast is OLH]PS` KYP]LU I` O\THU PTWHJ[Z ;OL KHTTPUN of coastal freshwater systems can have a ZPNUPÄJHU[ PTWHJ[ VU [OL ZHSPUP[` VM JVHZ[HS waters. Altering the salinity regimes of coastal waters can have far-reaching consequences for ÄZO IPYKZ V`Z[LYZ HUK ZLHNYHZZLZ
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The Texas Gulf Coast exhibits a strong salinity gradient, ^P[O SV^ ZHSPUP[` ^H[LYZ PU [OL <WWLY *VHZ[ HUK OPNO ZHSPUP[` waters in the southern bays and Laguna Madre. Image courtesy of Kalman Bugica and Mike Wetz.
WHERE DO WE GO FROM HERE?
COASTAL SUCCESSES )HɉU )H` =VS\U[LLYZ have donated their time to JVSSLJ[PUN KH[H VU [OL JOHUNPUN ^H[LY X\HSP[` VM )HɉU )H` ;OLPY ^VYR PZ LUVYTV\ZS` OLSWM\S [V ZJPLU[PZ[Z and managers. Sink Your Shucks H WYVNYHT associated with the Harte Research 0UZ[P[\[L OHZ YLZ[VYLK HWWYV_PTH[LS` 20 acres of oyster reef in the Mission-Aransas Estuary. Sink Your :O\JRZ OHZ WSHJLK TPSSPVU SIZ VM oyster shells on the bottom to serve as new oyster reefs. Red Snapper H JVTTLYJPHSS` PTWVY[HU[ ÄZO ZWLJPLZ OHZ ZOV^U PTWYV]LTLU[Z PU P[Z WVW\SH[PVUZ ;OLZL ÄZO HWWLHY [V IL ILULÄ[PUN MYVT [OL YLK\J[PVU VM ZOYPTW trawl bycatch.
A VISION FOR THE GULF OF MEXICO >L OVWL [OH[ YLWVY[ JHYKZ SPRL [OPZ VUL JHU IL created for the United States and Mexican Gulf *VHZ[ Z[H[LZ HUK *\IH ;OLZL YLWVY[ JHYKZ could easily be linked together to create an ,JVZ`Z[LT /LHS[O 9LWVY[ *HYK MVY [OL LU[PYL Gulf of Mexico. We also envision that the YLWVY[ JHYK JHU IL L_WHUKLK [V PUJS\KL ZVJPHS cultural, and economic factors to create a more holistic assessment of ecosystem health.
RECOMMENDATIONS
ABOUT THIS DOCUMENT
One of the greatest challenges in the Z[HRLOVSKLY ]HS\LZ WYVJLZZ PZ PKLU[PM`PUN KH[H and information that is useful for a regular ecosystem health assessment. Much of these data are not available for the Texas Coast or KV UV[ LUJVTWHZZ HSS VM [OL WLY[PULU[ SVJH[PVUZ HUK [PTLZ ;V PTWYV]L M\[\YL HZZLZZTLU[Z ^L YLJVTTLUK [OH[ TVUP[VYPUN IL L_WHUKLK [V ÄSS [OL KH[H NHWZ MVY LHJO VM [OL YLWVY[ JHYK LSLTLU[Z IPYKZ ÄZOLYPLZ ZLHNYHZZLZ ^H[LY quality and oysters).
;OPZ YLWVY[ JHYK ^HZ KL]LSVWLK [OYV\NO WHY[PJPWH[PVU VM L_WLY[Z on Texas Coast oysters, seagrass, water quality, birds, and ÄZOLYPLZ ;OL WYVQLJ[ I\PSKZ VU Z[HRLOVSKLY ]HS\LZ LZ[HISPZOLK K\YPUN [OL ,JV/LHS[O 4L[YPJZ 7YVQLJ[ H WHY[ULYZOPW IL[^LLU Harte Research Institute, Harwell Gentile and Associates, and the University of Maryland Center for Environmental Science.
Want to learn more? Visit the Harte Research Institute at: https://www.harteresearchinstitute.org/
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This document is a companion to the 2019 Texas Coast Ecosystem Health Report Card. Both documents can be accessed online at:
www.harteresearchinstitute.org ;OPZ KVJ\TLU[ KPZJ\ZZLZ PU NYLH[LY KL[HPS [OL KPɈLYLU[ PUKPJH[VYZ we used to assess the condition of the Texas coast of the Gulf of Mexico. It also shows how we measured the health of each of these indicators in the report card.
Texas Coast Bird Results
Texas coastal habitats support many bird species. During the breeding season, large colonies of spoonbills, herons, egrets, gulls, terns, and skimmers raise their `V\UN VU IH` PZSHUKZ 0U ^PU[LY TPSSPVUZ VM ^H[LYMV^S HUK ZOVYLIPYKZ ÄUK H ZHML haven where food is plentiful and the climate is mild. During migration, the Texas coast is an important hemispheric stopover where birds rest and refuel.
Why do we care?
Texas is the number one bird-watching destination in North America. With 400 species found along the coast, two-thirds of the state’s bird diversity resides near the Gulf. Iconic species like Piping Plover and Whooping Crane attract nature tourists. Nature tourism pumps hundreds of millions of dollars into the state’s economy and creates thousands of jobs, especially in coastal communities. Beyond economics, birds support ecosystems as predators, scavengers, and prey. )LJH\ZL IPYKZ Å` [OL` SPUR LJVZ`Z[LT WYVJLZZLZ HUK Å\_LZ PU ZWHJL HUK [PTL
Galveston Bay
Aransas Bay
Laguna Madre
Percent Change
55.0 to 81.8 25.0 to 54.9 0.0 to 24.9 -10.1 to -0.1 -20.1! to! -10.1
Texas Percent human population change (2000-2010): 20.6%
Many factors are driving conditions
)PYKZ MHJL THU` JOHSSLUNLZ VY Z[YLZZVYZ ;OLZL JHU IL UH[\YHS VY THU THKL HUK TH` HќLJ[ Z\Y]P]HS VY reproductive success, and if severe or continual, may cause population sizes to decrease. Stressors for birds include food shortages, disturbance, habitat loss or alteration, development, and climate change. How birds YLZWVUK [V Z[YLZZVYZ ]HYPLZ PU LHJO Z[HNL VM [OLPY HUU\HS J`JSL ;OL J\T\SH[P]L LќLJ[Z VM Z[YLZZVYZ IPYKZ LUJV\U[LY during migration, wintering, and breeding seasons in Texas have resulted in population declines in many species. One of the critical stressors for birds that are migrating and wintering in Texas is habitat quality. For birds that HYL IYLLKPUN KPZ[\YIHUJL HUK WYLKH[PVU TH` OH]L [OL NYLH[LZ[ LќLJ[ ,UZ\YPUN [OH[ Z[YLZZVYZ HYL LSPTPUH[LK VY minimized for birds in Texas coastal habitats is key to maintaining healthy bird populations.
Historical trends
:PUJL IPYKZ TPNYH[L HJYVZZ SHYNL KPZ[HUJLZ [OL Z[H[\Z VM HU` WVW\SH[PVU PZ HќLJ[LK I` [OL OLHS[O VM LJVZ`Z[LTZ throughout its range. Populations of many coastal bird species have decreased during the last few decades. 9LJVNUP[PVU VM WVW\SH[PVU KLJYLHZLZ PZ [OL ÄYZ[ Z[LW PU HKKYLZZPUN [OL JH\ZLZ VM KLJSPUL HUK ^VYRPUN [V^HYK species recovery. International Union for the Conservation of Nature (IUCN) data show that in the Western Hemisphere, populations of Mottled Duck, Lesser Scaup, and Least Sandpiper are decreasing while Great Egret and Forster’s Tern are increasing. Piping Plover, although currently increasing in North America, remains vulnerable to extinction because its geographic range is limited and its total population is only ~8000 individuals. Piping Plover populations have grown by about 50% since 1985 due to aggressive management of habitat on both wintering and breeding grounds, and reduction of stressors, such as disturbance, during the breeding season. However, these gains could be reversed easily if habitat loss were to again accelerate, or other stressors increase in severity. In Texas, the status of indicator species populations varies by region. On the upper coast, Great Egret, Mottled Duck, and Piping Plover have decreased over the last 20–40 years whereas populations are stable or increasing VU [OL TPKKSL HUK SV^LY JVHZ[HS HYLHZ ;OLZL [YLUKZ YLÅLJ[ [OL KPќLYLUJLZ PU OHIP[H[ H]HPSHIPSP[` L N SVZZLZ degradation due to coastal development, subsidence, etc.), and disturbance pressures that exist along the coast. Loss of habitat is the primary stressor implicated in declines on the upper Texas Coast and will likely continue to be the driving factor in the status of coastal bird populations now and for the foreseeable future. *VHZ[HS KL]LSVWTLU[ THRLZ P[ KPѝJ\S[ MVY JVHZ[HS LJVZ`Z[LTZ [V HKQ\Z[ [V ZLH SL]LS YPZL I` LZZLU[PHSS` ISVJRPUN landward or seaward movement across the landscape. This is particularly true on the upper Texas coast even if sea level increases by only 0.5 m; landward migration of wetlands is already restricted by existing urban land uses and levees.
Stability
While increasing populations are clearly indicative of “doing something right” and decreasing populations are clearly indicative of the opposite, stable populations may be the best that can be achieved given the limitations of habitat and other resources. Stability should be recognized as a good or even great outcome for areas where OHIP[H[ SVZZ PZ ZPNUPÄJHU[ HUK VY VUNVPUN 4HPU[HPUPUN Z\P[HISL OHIP[H[ [OH[ WYV]PKLZ JYP[PJHS YLZV\YJLZ MVY TPNYH[PUN wintering, and breeding birds means that stable populations are an achievement.
Methodology
:P_ IPYK ZWLJPLZ ^LYL JOVZLU [V YLWYLZLU[ [^V ZLHZVUHS N\PSKZ·^PU[LY TPNYH[PVU HUK IYLLKPUN·HUK ZL]LYHS OHIP[H[ ILOH]PVY N\PSKZ 4PNYH[PUN ^PU[LYPUN ZWLJPLZ PUKPJH[VYZ HYL 7PWPUN 7SV]LY ZPNO[ MVYHNPUN ZOVYLIPYK 3LHZ[ Sandpiper (tactile foraging shorebird), and Lesser Scaup (waterfowl). Breeding species indicators are Forster’s Tern (ground nester), Great Egret (shrub nester), and Mottled Duck (wetland nester). With the exception of Piping Plover (“Near Threatened”), all species are considered “Least Concern” by the International Union for the Conservation of Nature (IUCN). Data from Audubon’s Christmas Bird Count and the USGS Breeding Bird survey were used [V HZZLZZ [YLUKZ VU [OL ;L_HZ *VHZ[ +H[H ^LYL JVTWPSLK I` KLJHKL ;OLU Z[H[PZ[PJHSS` ZPNUPÄJHU[ KLJHKHS KPќLYLUJLZ PU [OL HI\UKHUJLZ VM ZWLJPLZ ^LYL \ZLK [V PKLU[PM` H IHZLSPUL KLJHKL ;OL TLKPHU HI\UKHUJL VM [OL baseline decade was used as an index value, and the counts of statistically non-random increases or decreases in HI\UKHUJLZ PU Z\IZLX\LU[ `LHYZ ZPNUPÄLK PUJYLHZPUN VY KLJYLHZPUN WVW\SH[PVU [YLUKZ
Texas Coast Seagrass Results
^HZ [OL ÄYZ[ Z`Z[LTH[PJ ZLHNYHZZ TVUP[VYPUN WYVNYHT PUP[PH[LK MVY [OL entire Texas coast, and the results have yet to be released. For Aransas Bay south, results are available for 2011–2017, during which percent seagrass cover of permanent stations bare and seagrass density at vegetated stations were stable on the midcoast (Aransas and Corpus Christi Bays, Figure 1 top). Percent seagrass cover of bare stations may be increasing in Upper Laguna Madre (Figure 1 middle) while decreasing in Lower Laguna Madre (Figure 1 bottom), although the record is too short to be conclusive.
Why do we care?
World-wide, seagrasses provide nursery habitat MVY JVTTLYJPHSS` HUK YLJYLH[PVUHSS` PTWVY[HU[ ÄZO and invertebrates; coastal protection from erosion; ^H[LY W\YPÄJH[PVU L N YLK\JPUN L\[YVWOPJH[PVU HUK phytoplankton blooms, and removing toxic organic compounds from water column and sediments); and sediment stabilization. They are a sink for atmospheric JHYIVU KPV_PKL HTVUN V[OLY ]HS\LK ZLY]PJLZ :WLJPÄJ to Texas, seagrasses provide wintering habitat for over half the world’s population of Redhead Ducks and essential nursery habitat for Red Drum and shrimp.
Many factors are driving conditions
Seagrasses are very unevenly distributed along the Texas coast, with 82% occurring in Laguna Madre, 18% in TPK JVHZ[ IH`Z HUK VUS` PU [OL .HS]LZ[VU )H` Z`Z[LT ;OPZ YLÅLJ[Z [OL Z[YVUN NYHKPLU[ PU ZHSPUP[` ^P[O Laguna Madre seldom fresher than seawater, the mid-coast bays fresher than seawater 15–70% of the time, and Galveston Bay fresher than seawater >85% of the time. Stressors such as sediment and nutrient inputs, “brown tide” algal blooms, and climatic variability can all lead to sharp changes in seagrass communities at the local to regional scale.
Historical trends
Seagrass mapping and monitoring have been so infrequent and variable in scope along most of the Texas coast that little can be said about trends. Based on approximately decadal mapping of Laguna Madre seagrasses from the 1960s to 1998 and annual sampling of permanent stations within seagrass meadows from 2011 to 2017, the [V[HS HYLH VM ZLHNYHZZ JV]LYHNL OHZ JOHUNLK SP[[SL /V^L]LY ZLHNYHZZ JVTT\UP[` JVTWVZP[PVU PZ PU Å\_ -PN\YL 2). Until ~2000, larger, more “climax” species like manatee grass gradually displaced the “pioneer” shoal grass. This process was interrupted in Upper Laguna Madre by multi-month episodes of hypersalinity (>50 ppt) in fall 2012 and summer 2013 that reduced the area dominated by manatee grass by two-thirds (Figure 2 top). In Lower Laguna Madre, Hurricane Alex in June 2010 caused large stormwater discharges into the lagoon that decreased salinity to near freshwater away from the Gulf outlet and eliminated manatee grass almost entirely from the whole system (Figure 2 bottom). Elsewhere along the coast, the two areas of immediate concern are Aransas Bay, where Hurricane Harvey made landfall August 25 2017, and Galveston Bay, into whose watershed Harvey dumped \UWYLJLKLU[LK HTV\U[Z VM ^H[LY ;OL ÄYZ[ HSS JVHZ[ ZHTWSPUN PU ^PSS YL]LHS OV^ HK]LYZLS` [OL YLTUHU[ HUK YLJLU[S` YL LZ[HISPZOLK ZLHNYHZZLZ VM [OL .HS]LZ[VU )H` Z`Z[LT OH]L ILLU PTWHJ[LK HSVUN ^P[O LќLJ[Z VU [OL long established and more extensive seagrass beds of Aransas Bay.
Seagrass cover (%)
Measures of Seagrass Cover Mid Coast
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Seagrass Species in Upper Laguna Madre changed over time Mean % cover all spp % stations bare
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Measures of Seagrass Cover Lower Laguna Madre
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Figure 2. Seagrass species composition in the Laguna Madre regions by time.
Figure 1. Measures of seagrass cover in coastal regions by time.
Methodology
Measures of seagrass condition are derived from data collected by the Texas Statewide Seagrass Monitoring Program, designed and carried out by Ken Dunton and colleagues at the University of Texas. From 2011 to 2017, his lab sampled seagrasses and water quality yearly from Aransas Bay to the south end of Laguna Madre. In 2018, the program was expanded to the rest of the bays along the Texas coast. Permanent locations were randomly set in each of 567 tessellated hexagons with >50% seagrass cover determined from vegetation maps NLULYH[LK K\YPUN [OL 56(( )LU[OPJ /HIP[H[Z (ZZLZZTLU[ :WLJPLZ JVTWVZP[PVU HUK JV]LY ^LYL obtained from four replicate 0.5 m2 quadrat samples per station at each of the cardinal directions from the vessel (texasseagrass.org). The mean % total quadrat cover for vegetated stations was used to determine trends in seagrass cover at all sites in each of the Mid Coast, Upper Laguna Madre, and Lower Laguna Madre reporting YLNPVUZ :JVYPUN VM [YLUKZ ^HZ IHZLK VU [OL ZPNUPÄJHUJL VM [OL [YLUK PU [OL WLYJLU[ JV]LY! MVY WVZP[P]L [YLUKZ Z[H[PZ[PJHSS` ZPNUPÄJHU[ [YLUKZ PU ZLHNYHZZ JV]LY ^P[O W ]HS\LZ ^LYL NYHKLK ¸(¹ HUK W ]HS\LZ # W 0.05 were graded “B”. Negative trends were graded the same way. No trend in seagrass cover was graded “C”.
Methodology
Texas Coast Oyster Results
Twenty years of oyster data from the Texas Parks and Wildlife Fisheries Independent Monitoring program were assessed to determine the current status and trends of oysters across the state. In the North region (Sabine Lake and Galveston Bay), the current status of oysters is poor (rated F) and abundances demonstrate a decreasing trend over time. In the Mid region (Matagorda, San Antonio and Aransas Bays), the current status of oysters is good to fair with stable abundances over time. Minimal natural oyster populations occur in Corpus Christi Bay (Mid region), as well as in the Upper and Lower Laguna Madre; no long-term monitoring data are available to determine status and trends of oysters in these systems.
Why do we care?
Oysters are important ecological and economic YLZV\YJLZ (Z Z\ZWLUZPVU MLLKLYZ [OL` ÄS[LY IH` ^H[LYZ and may mitigate excessive nitrogen loads. As reefbuilders, oysters create three-dimensional complex OHIP[H[ MVY U\TLYV\Z ÄZO HUK PU]LY[LIYH[LZ LUOHUJPUN recreational angling. Oyster reefs can act as natural breakwaters, protecting shorelines from erosion and reducing wetland loss. Oysters also support a robust seafood industry, generating over $16 million annually in Texas over the past decade.
Many factors are driving conditions
Declines in the abundance of oysters are a consequence of habitat loss, hydrologic alterations, water quality degradation, resource overharvest, disease, and storms. Because oysters depend on a delicate balance of salt and freshwater, they are sensitive to changes in salinity regime. After Hurricane Harvey in 2017, a severe oyster mortality event occurred along the upper coast due to massive inputs of freshwater that decreased salinity below oyster tolerance levels. Increasing salinities can also harm oysters. Upstream water diversions and reduced MYLZO^H[LY PUÅV^ JHU PUJYLHZL V`Z[LY TVY[HSP[PLZ I` HSSV^PUN THYPUL WYLKH[VYZ HUK KPZLHZLZ [V [OYP]L ,_JLZZ nutrient inputs to coastal waters can lead to hypoxic areas where low oxygen stresses oysters and leads to higher mortalities. Oyster harvest occurs by dragging a dredge along the bay bottom. Because free-swimming larval oysters depend on the shells of older generations for attachment and growth, when oyster harvests occur at unsustainable rates, the lack of shells inhibits natural recovery processes and essential habitat is lost. Poor or declining populations of oysters in Texas likely result from the interaction of these and other factors.
Historical trends
6`Z[LY YLLMZ HYL HTVUN [OL TVZ[ [OYLH[LULK THYPUL OHIP[H[Z VU LHY[O /PZ[VYPJHSS` V`Z[LY ÄZOLY` KL]LSVWTLU[ PU the U.S. followed human population centers as they expanded down the east coast and into the Gulf of Mexico, ^P[O V`Z[LY ÄZOLYPLZ PU ;L_HZ Z[HY[PUN PU [OL Z ;L_HZ HSZV OHZ H SVUN OPZ[VY`·MYVT H[ SLHZ[ HZ MHY IHJR HZ [OL 1930s—of removing oyster shells for commercial use, including for the production of lime and poultry feed, for \ZL PU JVUJYL[L HNNYLNH[L HUK YVHK JVUZ[Y\J[PVU *VU[LTWVYHULV\ZS` [OL LќLJ[ VM KLYTV KPZLHZL MHJPSP[H[LK by the high salinities and temperatures standard to Texas estuaries, has caused massive mortalities of oysters across the Gulf of Mexico. The overexploitation of oysters and shell resource, in combination with contemporary environmental stressors such as storms, droughts, and disease, will continue to challenge oyster sustainability across Texas.
Oyster reefs face threats from a variety of environmental factors. Overharvesting oyster reefs can diminish shell substrate for oyster larvae to colonize. In addition, decreased freshwater inflow through damming can raise salinity , and runoff from urban and agricultural sources can decrease available oxygen for oysters and bury oyster reefs.
Methodology For the regional evaluation criteria for the report card, the North region includes Sabine Lake and Galveston Bay. Methodology The Mid region includes Matagorda, San Antonio, and Aransas Bays. Corpus Christi Bay is within the Mid region
but TPWD does not collect oyster count data there. Current status was determined by comparing 5-year average oyster abundance (2011–2015) to quartiles of abundance calculated using all years (1986–2015). Trends were determined by assessing Spearman correlation between oyster abundance and years. Adapting this approach to an A-F rating scale, North = F (because poor and decreasing), Mid = C (because it was borderline “fair”), <34 $ 5 ( HUK 334 $ 5 ( *VHZ[^PKL [OL V]LYHSS ZJVYL $ + ZWSP[[PUN [OL KPќLYLUJL MVY [OL YLNPVUZ [OH[ OH]L scores). Note that ULM and LLM have very minimal natural oyster populations; we have no data to assess status HUK VY [YLUKZ
Texas Coast Fisheries Results
;OL ;L_HZ JVHZ[ Z\WWVY[Z H KP]LYZL HYYH` VM PUZOVYL HUK VќZOVYL ÄZOLYPLZ MYVT ÄUÄZO Z\JO HZ 9LK +Y\T :WV[[LK :LH[YV\[ HUK :V\[OLYU -SV\UKLY [V invertebrates including shrimp and Blue Crabs. These resources support vital ecological and economic roles. Understanding and maintaining the sustainability of [OLZL ÄZOLYPLZ PZ RL` [V H OLHS[O` .\SM VM 4L_PJV
Why do we care?
;L_HZ» ÄZOLYPLZ HYL IPSSPVU KVSSHY PUK\Z[YPLZ HUK create thousands of jobs. Aside from the obvious LJVUVTPJ ILULÄ[Z ;L_HZ» ÄZOLYPLZ HSZV WYV]PKL YVI\Z[ recreational opportunities that are part of the region’s historical and cultural fabric. Monitoring the health of RL` ÄZOLYPLZ PZ JYP[PJHS [V JVUZLY]PUN [OPZ YLZV\YJL MVY future generations to use and enjoy.
Many factors are driving conditions
,]LY` ÄZOLY` MHJLZ JLY[HPU JVUKP[PVUZ [OH[ JHU ULNH[P]LS` HќLJ[ [OL WVW\SH[PVU ;OLZL JVUKP[PVUZ VY Z[YLZZVYZ JHU IL UH[\YHS VY THUTHKL 0U HKKP[PVU UV[ L]LY` ÄZOLY` VY HYLH YLZWVUKZ [V Z[YLZZVYZ PU [OL ZHTL THUULY TLHUPUN [OH[ Z[YLZZVYZ T\Z[ IL L]HS\H[LK I` ZWLJPLZ HUK I` YLNPVU ,ќLJ[P]L THUHNLTLU[ OHZ YLZ\S[LK PU OLHS[O` Z\Z[HPUHISL WVW\SH[PVUZ MVY THU` VM ;L_HZ» ÄZOLYPLZ /V^L]LY V]LYOHY]LZ[PUN PSSLNHS ÄZOPUN KPZJHYK TVY[HSP[` KPZLHZL PUJYLHZLK ^H[LY [LTWLYH[\YLZ HUK H Z\P[L VM WO`ZPJHS JOHUNLZ Z\JO HZ KLJYLHZLK MYLZO^H[LY PUÅV^ OH]L [OL WV[LU[PHS [V KLZ[HIPSPaL ZL]LYHS ÄZOLYPLZ HSVUN [OL ;L_HZ JVHZ[
Historical trends
4HU` ÄZO WVW\SH[PVUZ [OH[ HYL HI\UKHU[ HSVUN [OL ;L_HZ JVHZ[ [VKH` ^LYL VUJL ULHY JVSSHWZL :JPLUJL IHZLK ÄZOLYPLZ THUHNLTLU[ JV\WSLK ^P[O ^PZL JVUZLY]H[PVU OH]L SLK [V KYHTH[PJ YLJV]LY` MVY THU` ÄZOLYPLZ >VYSK JSHZZ YLZV\YJL TVUP[VYPUN PTWYV]LK YLZLHYJO HUK LTLYNPUN [LJOUVSVNPLZ OH]L HSSV^LK ÄZOLYPLZ THUHNLYZ [V KL[LJ[ JOHUNLZ [V H ÄZOLY` THRL [OL TVZ[ PUMVYTLK KLJPZPVUZ HUK PTWSLTLU[ WYVHJ[P]L THUHNLTLU[ Z[YH[LNPLZ ;VNL[OLY [OLZL HќVYK ;L_HZ ^VYSK JSHZZ ÄZOLYPLZ 7YVWLY THUHNLTLU[ OHZ SLK [V WSLU[PM\S WVW\SH[PVUZ VM 9LKÄZO :WV[[LK :LH[YV\[ )SHJR +Y\T HUK .\SM :OYPTW KLZWP[L OLH]` ÄZOPUN WYLZZ\YL :[YLZZVYZ [V [OLZL ÄZOLYPLZ OH]L OHK TPUPTHS LќLJ[ VU [OLPY WYVK\J[P]P[` Monitoring data indicate that they have been stable, and in some cases increasing, over the past decade, WHY[PJ\SHYS` PU :[H[L ^H[LYZ :VTL JOHSSLUNLZ Z[PSS L_PZ[ ^P[O [OL :V\[OLYU -SV\UKLY HUK )S\L *YHI ÄZOLYPLZ ^OPJO have exhibited their lowest population sizes and an overall decline during the past 20 years. Abundance and SHUKPUNZ KH[H MVY [OLZL ZWLJPLZ Z\NNLZ[ [OH[ V]LYÄZOPUN VY V[OLY LU]PYVUTLU[HS MHJ[VYZ TH` IL JH\ZPUN [OLPY decline and preventing recovery. Additional assessments and regulations may be required to facilitate rebuilding these populations.
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Methodology
*H[JO WLY \UP[ LќVY[ KH[H ^LYL VI[HPULK MYVT [OL ;L_HZ 7HYRZ HUK >PSKSPML +LWHY[TLU[ MVY LHJO ZWLJPLZ ^P[OPU nine bay systems. These data were collected from a long-standing monitoring program using data from 1980 [V [OL WYLZLU[ +H[H ^LYL WHYZLK I` ZWLJPLZ ^P[O IH` Z`Z[LTZ ILPUN WVVSLK I` YLNPVU 9LNYLZZPVUZ ^LYL Ä[ [V establish long-term trends and short-term trends and to determine if recent trends were stable, increasing, or decreasing. Letter grades were established based on the change of slope for these analyses as well as stressors MHJPUN [OLZL ÄZOLYPLZ
Methodology Methodology
Lower Laguna Madre and Upper Laguna Madre Expansion ;OL <WWLY HUK 3V^LY 3HN\UH 4HKYL Z`Z[LTZ HYL RUV^U MVY [OLPY KP]LYZL HUK HI\UKHU[ ZWVY[ÄZO WVW\SH[PVUZ 9LKÄZO )SHJR +Y\T HUK :WV[[LK :LH[YV\[ U\TILYZ HYL H[ HSS [PTL OPNOZ KLZWP[L PUJYLHZPUN ÄZOPUN WYLZZ\YL However, Blue Crab and Southern Flounder populations are decreasing at faster rates in these areas than HU`^OLYL LSZL VU [OL ;L_HZ *VHZ[ -HJ[VYZ SPRL KPZLHZL HUK KLJYLHZLK MYLZO^H[LY PUÅV^ THRL [OLZL ÄZOLYPLZ KPѝJ\S[ [V Z[HIPSPaL 4VYL YLZLHYJO PZ JY\JPHS [V LS\JPKH[L WYVISLT MHJ[VYZ HUK HSSL]PH[L PTWHJ[Z VU [OLZL ÄZOLYPLZ
Texas Coast Water Quality Results
The Texas coast consists of nearshore coastal waters as well as seven major estuaries, each of which has one primary bay and one or more secondary bays. Each system has a unique water quality signature, which is one of the most PTWVY[HU[ PUÅ\LUJLZ VU [OL [`WLZ VM OHIP[H[ HUK VYNHUPZTZ [OH[ PUOHIP[ [OL Z`Z[LT The report card contains a brief snapshot of water quality conditions in the estuaries. Future studies will assess a broader suite of water quality indicators (e.g., plastics, heavy TL[HSZ HUK ^PSS HSZV PUJS\KL [HYNL[LK ZP[L ZWLJPÄJ HZZLZZTLU[Z
Why do we care?
Estuarine and nearshore coastal waters are among the most productive ecosystems on the planet, providing food resources and habitat for ecologically HUK LJVUVTPJHSS` PTWVY[HU[ ÄZO HUK ZOLSSÄZO ZWLJPLZ recreational opportunities, and other important ecosystem services. Without good water quality, this WYVK\J[P]P[` HUK HIPSP[` [V Z\WWVY[ ÄZOLYPLZ ^V\SK UV[ be possible.
Many factors are driving conditions
Coastal waters worldwide are being exposed to an increasingly complex suite of stressors. On lands surrounding [OL JVHZ[ \YIHUPaH[PVU HUK PU[LUZP]L HNYPJ\S[\YL JHU ULNH[P]LS` HќLJ[ [OL ^H[LY X\HSP[` VM Z[YLHTZ YP]LYZ and coastal waterbodies. One of the most pervasive problems is a process called eutrophication, where too much nitrogen and phosphorus input to a waterbody leads to excessive algal growth and overall water quality degradation. Climate stressors, such as increasing air and water temperature, can speed up this algal growth, and at the same time reduce the oxygen content of a waterbody. In Texas, there is growing concern about increasing O\THU MYLZO^H[LY ULLKZ ^OPJO YLK\JLZ [OL HTV\U[ VM MYLZO^H[LY [OH[ ÅV^Z [V [OL JVHZ[ HUK SLHKZ [V PUJYLHZPUN ZHSPUP[` PU JVHZ[HS ^H[LYZ ;OL J\T\SH[P]L LќLJ[Z VM [OLZL WLY[\YIH[PVUZ VM[LU PUJS\KL KLJSPUPUN ^H[LY X\HSP[` HUK ecosystem health.
Historical Trends
Analysis of historical data on key water quality variables shows that the Texas coast has fair to good overall water quality conditions, but with some localized areas of concern. For example, levels of chlorophyll (an indicator of HSNHS IPVTHZZ HYL OPNO HUK PUJYLHZPUN PU )HѝU )H` HUK <WWLY 3HN\UH 4HKYL ([ [OL ZHTL [PTL KPZZVS]LK V_`NLU levels are decreasing. Both of these indicate that the system is experiencing symptoms of nutrient pollution. In contrast, chlorophyll levels are largely decreasing in Nueces Bay. This is likely a result of reduced freshwater inputs of nutrients due to damming of its river systems. Thus, the system is being “starved” of the nutrients that would otherwise support its productivity. Another major water quality concern is a long-term increase in the salinity of mid-coast estuaries from Nueces Bay to Matagorda Bay. This is largely a consequence of increasing human freshwater demands in the watersheds of these estuaries.
Houston
Corpus Christi Laguna Madre
Legend Dams
Urban Wastewater
Nutrient input
Decreasing oxygen
Increasing algae
Farms
Freshwater input
Increasing salinity
Methodology ;V X\HU[PM` YLNPVU ZWLJPÄJ H]LYHNLZ VM ]HYPV\Z ^H[LY X\HSP[` ]HYPHISLZ HZ ^LSS HZ SVUN [LYT ^H[LY X\HSP[` [YLUKZ Methodology along the Texas coastline, data were obtained from the Texas Commission on Environmental Quality’s (TCEQ’s)
:\YMHJL >H[LY 8\HSP[` 4VUP[VYPUN :>84 WYVNYHT O[[WZ! ^^^ [JLX [L_HZ NV] ^H[LYX\HSP[` TVUP[VYPUN ;OL SWQM program collects water samples on a quarterly basis from all bay systems on the Texas coast. SWQM sites chosen for trend analysis had active monitoring up to 2016, and also had at least 20 years of data (back to 1996 or earlier). Spatial patterns in water quality were calculated using averages of data collected between 2009 HUK 2LUKHSS»Z єH YLNYLZZPVU ^HZ \ZLK [V KL[LYTPUL YLSH[PVUZOPWZ IL[^LLU ^H[LY X\HSP[` ]HYPHISLZ HUK [PTL (Kendall 1955).
Acknowledgments The Texas Coast Ecosystem Health Report Card was created based on collaborations begun under the Harte Research Institute’s Gulf EcoHealth Metrics Initiative. The report card project was led by Drs. Larry McKinney and Wes Tunnell (Harte Research Institute, Texas A&M University-Corpus Christi), and Heath Kelsey and Bill Dennison (University of Maryland Center for Environmental Science). The Texas ecosystem team leaders are Greg :[\Ua HUK 1Lќ -YHUJPZ ÄZOLYPLZ *OYPZ 6U\M (seagrasses), Jennifer Pollack (oysters), Mike Wetz (water quality) and Kim Withers (birds). Design and graphics by James Currie and Emily Nastase (University of Maryland Center for Environmental Science). Photos by Harte Research Institute, Quentin Hall, Dr. Mike Wetz, James Currie, Scott Murray, Jace Tunnell, Elizabeth Smith, Andrea Westmoreland, Terry Ross, and Charleen Mullenweg.
Texas A&M University -- Corpus Christi Harte Research Institute for Gulf of Mexico Studies 6300 Ocean Drive, Unit 5869 Corpus Christi, Texas 78412 361-825-2020 harteresearchinstitute.org info@harteresearchinstitute.org