Upper Gulf Coast Of Texas Research Articles

Diversity of Citrus tristeza virus Strains in the Upper Gulf Coast Area of Texas.

Citrus tristeza virus (CTV) in Texas was first reported in the 1950s and has since been sporadically reported in the residential areas in the Upper Gulf Coast region. Because the major rootstock for commercial citriculture in South Texas is sour orange, which is susceptible to CTV decline, the spread of CTV into South Texas can pose a great threat to Texas citrus industry. Thirty-six CTV-positive samples, collected during surveys conducted in the Upper Gulf Coast area of Texas from 2013 to 2018, were first analyzed by strain-specific real-time PCR (RT-PCR) targeting various regions of CTV Open reading frame (Orf) 1a and then by amplicon sequencing derived from p25 and p20 region of CTV genome. Among 36 samples, 33 were successfully genotyped by strain-specific RT-PCR and by amplicon sequencing followed by phylogenetic analysis. Variability in the detection of CTV strains was observed over a 6-year period. In 2013, T3 and T30 were the only strains detected in the Upper Gulf Coast of Texas, but in further surveys until 2018, additional strains were detected, including T36, VT, and RB. Mixed infections were also detected in 14 samples comprising about 42% of CTV samples examined in the study. Although genotyping mixed infection samples by targeting Orf 1a and full-length p25, residing in the 5' and 3' region of the CTV genome, respectively, confirmed the presence of multiple strains in these samples, incongruent genotyping data were observed. These findings suggested that the current status of CTV strain diversity in Texas Upper Gulf Coast region might have been established by multiple introductions of CTV-infected plant materials for propagation and with a potential recombination in planta.

Stink bug species composition and relative abundance of the redbanded stink bug (Hemiptera: Pentatomidae) in soybean in the upper gulf coast Texas.

Stink bugs are the primary arthropod soybean pests in the southern United States. Historically, important stink bug species damaging soybeans in the southern United States included the southern green stink bug Nezara viridula (L.), the green stink bug Chinavia hilaris (Say), and the brown stink bug Euschistus servus (Say) (Hemiptera: Pentatomidae). The redbanded stink bug, Piezodorus guildinii (Westwood), has recently become an economic pest of soybean in the southern region of the United States, especially in Louisiana and Texas. Little is known about current stink bug species composition and relative abundance in Texan soybean agro-ecosystems. To fill this gap, commercial soybean fields in the Upper Gulf Coast of Texas were sampled weekly during the growing season using a sweep net throughout R2 (full flowering) to R7 (beginning maturity) from 2011 to 2013. Adults and nymphs (third, fourth, and fifth instars) of redbanded stink bug, southern green stink bug, green stink bug, and brown stink bug were counted per 25 sweeps. The relative abundance of redbanded stink bug was significantly higher than any other stink bug species throughout 2011-2013. Over 65% of the total population of major stink bugs collected during this period were redbanded stink bugs and ≍19% were southern green stink bugs. The highest redbanded stink bug densities and the highest ratio of redbanded stink bug nymphs to adults were recorded at R7. Results from this study show that redbanded stink bug has become the predominant stink bug species in soybean in the Upper Gulf Coast of Texas.

Influence of biotic and abiotic factors on annual aboveground biomass of an intermediate coastal marsh

Annual production of vegetation is an important indicator of various ecosystem processes in coastal marshes; many factors, both biotic and abiotic, can influence production of aboveground biomass. Using a 14-year data set, we evaluated the relative influence of 38 biotic and abiotic factors on annual aboveground biomass of an intermediate coastal marsh on the upper Gulf Coast of Texas. We used visual obstruction (VO) measurements as a surrogate variable in a prediction model to estimate available aboveground biomass in the marsh. Available biomass was greatest (3.34 kg/m 2 ) when sampling site was flooded. Plant growth form, type of animal present, and composition of the ground cover influenced biomass of the marsh. Presence of insects was related to biomass (regression beta weight 5 0.28), uniquely accounting for 7.6% of the incremental variance in biomass. The presence of moderate amounts of litter was also related to available biomass (beta weight 5 0.86). Soil capping had little or no influence on aboveground biomass. Implementing standard protocols for long-term vegetation monitoring can be cost and time intensive. Our results suggest quantitative measurement of VO and qualitative observation of few variables (standing water, insects, and litter) measured annually can yield a reasonable assessment of aboveground biomass of intermediate coastal marshes.

Biogeochemical behavior of organic carbon in the Trinity River downstream of a large reservoir lake in Texas, USA

Dissolved and particulate organic carbon concentrations were measured and annual loads estimated for the Trinity River, the main freshwater input source to Galveston Bay, which lies on the upper Gulf coast of Texas, USA, during 2000–2001. This river drains the forested lowlands south of a relatively large reservoir lake, Lake Livingston. A weak relationship between dissolved organic carbon (DOC) and Q TR indicated hydrologic control but separation of the data, based on individual discharge events, was necessary to improve interpretation. For instance, the first rain of the season resulted in only a modest increase in DOC concentrations and led to an inverse relationship with discharge, due to decreased lateral flow and increased infiltration of rainwater, with the lower flows being more efficient at DOC leaching from soils. In contrast, a long duration high discharge river crest event resulted in an opposite trend, i.e. a linear increase in DOC with increasing discharge rates. A short duration high discharge tropical storm showed reduced Trinity River DOC concentrations and the highest POC concentrations measured, likely resulting from the relatively short duration, and minimal contact time, of this event. In contrast to DOC, the concentrations of particulate organic carbon, POC (mg C l −1) were linearly correlated to suspended particulate matter (SPM) concentrations and accounted for between 10 and 12% of the total suspended load at low discharge but decreased to ∼2% at high discharge. This suggests dilution by larger particles with a reduced organic carbon content, possibly silicate minerals, more readily resuspended at elevated levels of discharge. The annual total organic carbon (TOC) load to Galveston Bay, estimated from the slope of the daily load vs. discharge relationship, was 11.2×10 10 g C and calculated export coefficients (g C m −2 year −1) were in good agreement with previous results. Using this relationship, accurate assessments of TOC flux inputs to Galveston Bay over the past quarter-century and in the future are possible by obtaining annual Trinity River discharge rates, which are readily available from the USGS. Comparing DOC riverine inputs to benthic sources in Trinity Bay, measured directly on the same day, indicates that the sediments contribute approximately 20% of total inputs of DOC to Trinity Bay. However, assuming a constant benthic source during low-flow conditions, which can occur for periods of up to 14 months in this region of Texas, benthic fluxes would account for >80% of the total inputs into Trinity Bay. At high levels of discharge, the Trinity River discharges ∼1.0×10 9 g C day −1 and dominates DOC inputs to Trinity Bay.

Identification of Rhizoctonia solani AG-UNK from Rice and Rice Fields in Texas as AG-11.

A survey of Texas rice fields in 1984 and 1985 yielded collections of Rhizoctonia solani AG-1 IA (causal agent of sheath blight of rice), R. oryzae (causal agent of sheath spot of rice), and a collection of eight multinucleate Rhizoctonia solani-like isolates that would interanastomose, but not anastomose, with tester isolates of AG-1 through AG-8 (representing those available at that time). In 1985, the isolates were characterized as R. solani AG-UNK (2). Isolates were recovered as atypical sclerotia from elutriated field soils in rice-soybean and rice-fallow rotations. Isolates also were recovered from late-season stem lesions nearly identical to those associated with sheath spot disease and from rice residues at locations throughout the upper Gulf Coast of Texas but at extremely low frequencies compared with recovery of R. solani AG-1 IA and R. oryzae. Teleomorphs of R. solani AG-UNK were observed during middle to late season on rice sheaths and matched descriptions of Thanatephorus cucumeris. Isolates were pathogenic on rice and soybean foliage in greenhouse trials but caused no significant yield losses when inoculated on adult rice plants (50 days after emergence) in field trials (2). Isolates exhibited mean hyphal diameters of 5.1 μm, averaged 8.3 nuclei per penultimate cell, grew 0.53 mm/h at 28°C on potato dextrose agar, and were negative in phenol tests (2). From samples maintained in storage during the past 15 years, the isolates have now been identified as AG-11 based on positive anastomosis with tester strains of AG-11 (1). This report records the occurrence of AG-11 in Texas, establishes the identity of the AG-UNK group, and expands the known geographic range of AG-11 in the United States.

Age Structure in a Population of Red-Spotted Newts from the Allegheny Plateau of Maryland

The red-spotted newt, Notophthalmus viridescens, is widely distributed in North America east of a line stretching from southern Quebec to the upper Gulf Coast of Texas (Mecham, 1967; Conant, 1975). The species exhibits a complex life history which includes an aquatic larva, a terrestrial juvenile (eft), and an aquatic adult. The duration of these life history stages is variable. In upland populations, larvae characteristically hatch during the spring and summer and engage in post-larval migrations during the late summer and early fall (Hurlbert, 1970; Healy, 1975a; Gill, 1978a, b). Juveniles spend from 2-7 years as terrestrial efts before returning to the aquatic habitat to spend 1-9 years as mature, sexually active adults (Hurlbert, 1969; Pough, 1971; Healy, 1975b; Gill, 1978a, b, 1985). In coastal plain populations, the terrestrial eft phase is rare and in some localities may be omitted altogether (Noble, 1926, 1929; Healy, 1975a). In these populations, larvae metamorphose directly into adults and reach sexual maturity after two years. Historically, estimations pertaining to the age structure of various populations of the red-spotted newt have been based on one of two techniques: (1) a comparison of size-frequency histograms derived from sequential field collections; or (2) multi-year mark and recapture techniques. In the first technique, accuracy is influenced by variability in individual growth rate. The growth rate of newts comprising each of the life history stages is directly proportional to the amount of food consumed (Springer, 1909). Food consumption depends upon resource availability and the intensity and duration of individual activity. The activity of terrestrial efts is positively correlated with humidity and temperature (Healy, 1973), while that of aquatic juveniles and adults is inversely correlated with temperature (Springer, 1909). The use of a mark and recapture technique to estimate age structure maximizes accuracy, but requires a prolonged and often impractical time commitment (see Gill, 1985). In this report we apply the technique of skeletochronology to estimate the age structure and relative duration of the eft and adult life history stages of redspotted newts taken during a single sampling event. Seventy-six red-spotted newts (10 larvae, 36 efts and 30 adults) were collected from the Blue Ridge Physiographic Province of western Maryland (elevation 800 m) during June, 1984. The site consisted of a eutrophied farm pond surrounded by steep slopes covered by a second-growth, mixed mesophytic forest. Larvae and adults were collected from the shal-

Oil and Gas Developments in Upper Gulf Coast of Texas in 1989

Onshore drilling in the upper Gulf Coast of Texas during 1989 totaled 638 wells, a 21.6% decrease from 1988's total of 814 wells. Exploratory drilling remained at the same level, but development drilling declined 30.2% from 1988. Thirty-four new-field discoveries resulted from drilling 141 new-field wildcat wells in 1989, a 23.6% success rate. Fifty-three other wildcat discoveries resulted from drilling new-pool, deeper pool, or extension wells with a 60.2% success rate. The Eocene trend was once again the most active exploratory trend onshore with 40.6% of the onshore drilling; the Oligocene and Cretaceous trends had 25.3% and 3.1% of the onshore exploration activity, respectively. Offshore exploratory drilling in 1989 totaled 74 wells, a 32.1% decrease from 1988. Development drilling offshore nearly tripled with 174 development wells drilled in 1989 compared to 64 wells drilled in 1988. The exploratory success rate offshore was 31.1%. Exploration activity resulted in 20 new-field discoveries and 3 new-pool, deeper pool, or extension discoveries. Forty exploratory dry holes were drilled offshore in 1989. Offshore, the Miocene trend was most actively explored with 8.1% of the exploratory drilling in 1989 (66 wells were listed as undesignated).

Sand Transport in Texas Tidal Inlet

Rollover Pass is a manmade, artificially‐stabilized tidal inlet on the upper Gulf Coast of Texas. The magnitude of the net annual sand transport through the inlet was estimated: (1) As a percentage of the net longshore transport; (2) from excess beach erosion downdrift of the Pass; and (3) from dredge‐material volumes for the Intracoastal Waterway landward of the inlet. Limited direct measurements of sand transport were also made. The excess beach erosion downdrift of the Pass was between about 9,000 and 26,000 cu yd/yr (6,700 and 20,000m3/yr), which was in general agreement with the estimation of net annual sand transport calculated as a percentage of longshore transport. Net annual transport through the inlet estimated from extensive data on dredging rates was nearly an order of magnitude greater than estimates based on longshore transport and beach erosion.

Oil and Gas Developments in Upper Gulf Coast of Texas

Onshore drilling in Texas Railroad Commission District 3 totaled 814 wells in 1988, a 1% decrease from 1987's total of 822 wells. Exploratory drilling increased by 18.0%; development drilling declined 6.8%. Thirty-six new field discoveries resulted from drilling 128 new-field wildcats for a 28.1% success rate. Other exploratory wells (new-pool wildcats, deeper pool tests, shallower pool tests, and outpost-extension wells) had a 56.0% success rate; 100 wells were drilled in this category. The developmental success rate was 69.3% with 586 development wells drilled in 1988. The Eocene trend was the most active with 28.5% of the activity.. The Wilcox and Yegua Formations were the primary targets, receiving 47.6% and 46.2% of the Eocene activity, respectively. Offshore exploratory drilling in District 3 totaled 109 wells, a 70.3% increase from 1987's total of 64. Development drilling totaled 64 wells, a 28.0% increase from 1987 activity. The offshore exploratory success rate was 6.2% for new-field wildcats and 58.3% for other exploratory wells. The developmental success rate was 75.0%.

Oil and Gas Developments in Upper Gulf Coast of Texas in 1987

Onshore drilling in the upper Gulf Coast of Texas during 1987 totaled 822 wells, a 19.8% decrease from 1986's total of 1,025 wells. Exploratory drilling declined 17.5%, and development drilling decreased 20.5% from 1986. Twenty-two new-field discoveries resulted from drilling 123 new-field wildcat wells in 1987, for a 17.9% success rate. Forty-five other wildcat discoveries resulted from drilling new-pool, deeper pool, or extension wells, with a 64.3% success rate. The Eocene trend was the most active exploratory trend onshore with 38.9% of the onshore drilling; the Oligocene and Cretaceous trends had 27.4% and 26.4% of the onshore exploration activity, respectively. Offshore exploratory drilling in 1987 totaled 64 wells, an 18.5% increase from 1986. Development drilling offshore declined 51.0% with 50 development wells drilled in 1987 compared to 1986's total of 102 wells. The exploratory success rate offshore was 17.2%. Exploration activity resulted in 6 new-field discoveries and 5 new-pool, deeper pool, or extension discoveries. Fifty-three exploratory dry holes were drilled offshore in 1987. Offshore, the Miocene trend was most actively explored, receiving 59.4% of the exploratory drilling in 1987.

Oil and Gas Developments in Upper Gulf Coast of Texas in 1986

Onshore drilling in the upper Gulf Coast of Texas in 1986 was down 52.2% from 1985. Onshore exploratory drilling was down 46.3%, and development drilling was down 53.7%. Offshore drilling was down 22.0% from 1985. Offshore exploratory drilling was down 34.1%, but development drilling was down only 13.6%. The Eocene and Oligocene trends were the most active in the onshore area. The Miocene was the most active offshore trend. Onshore seismic activity was down 12.7% from 1985. The Eocene trend had more than half of the seismic activity in the onshore. Offshore seismic activity was down 31.7% from 1985. More than half of the offshore activity was conducted in the High Island area. Although the onshore rig count dropped 58% during 1986 and spot gas prices fell by 48%, signs of stabilization in gas prices could set the stage for future improvements in industry activity.

Oil and Gas Developments in Upper Gulf Coast of Texas in 1985

Onshore drilling in the upper Gulf Coast of Texas during 1985 totaled 2,143 wells on an as-reported basis, a 4.5% increase from 1984's total of 2,050 wells. Exploratory drilling was up 7.4%, whereas development drilling increased 3.8% from 1984. Four hundred thirty-six exploratory wells and 1,707 development wells were drilled during 1985. There were 45 new-field discoveries onshore in 1985 out of 257 new-field exploratory wells, for a 17.5% success rate. The average depth for these wells was 9,716 ft. There were 148 other wildcat discoveries and 31 failures for an 82.7% success rate in the category of new-pool, deeper pool, and extension wells. The Oligocene trend was the most active trend onshore in 1985 with 45.1% of the drilling, followed by the Eocene trend with 36.9%. Offshore exploratory drilling in 1985 totaled 82 wells on an as-reported basis. Fourteen gas discoveries, 2 oil discoveries, and 66 dry holes were reported. The overall success rate was 19.5%, a significant increase from the 12% success rate reported in 1984. Onshore geophysical activity decreased significantly in 1985 to 385 crew-weeks from 1984's total of 937 crew-weeks. Offshore activity was also down in 1985 with 202 crew-weeks compared to 317.5 crew-weeks reported in 1984.

Oil and Gas Developments in Upper Gulf Coast of Texas in 1984

Wells drilled in the Upper Gulf Coast of Texas during 1984 totaled 1,973, almost the same as 1983's total of 1,979 wells. Onshore exploratory drilling continued to decrease, with 329 wildcats drilled compared to 426 in 1983 and 505 in 1982. Development drilling accounted for 83% of all onshore wells, up 6% from the 2 previous years. There were 36 new-field discoveries in 1984 with an average depth of 10,163 ft and a success rate of 20%. The 96 other exploratory discoveries had a success rate of 64%. The Oligocene trend was the most active, with 43% of the wildcat drilling, followed by the Eocene trend, with 39%. Offshore exploratory drilling was up sharply from 1983. A total of 57 wildcats were completed during 1984, up from 37 in 1983. Seven wildcats were successful gas completions for a 12% success rate (there were no oil completions). An additional 38 wildcats drilled during 1984 were classified as suspended at year end. Onshore geophysical activity increased in 1984 to 937 crew-weeks from 1983's 894 crew-weeks. Offshore activity hit an all-time high for the third consecutive year with 317.5 crew-weeks.

Oil and Gas Developments in Upper Gulf Coast of Texas in 1983

Wells drilled in the Upper Gulf Coast of Texas during 1983 totaled 1,979, down 23% from the 1982 total of 2,581. Onshore exploratory drilling continued to decrease, with 426 wildcat wells drilled compared to 505 wells in 1982 and 581 in 1981. Development drilling accounted for 77% of all onshore wells, virtually unchanged from the previous 3 years, but the 1,422 wells drilled was 25% fewer than in 1982. There were 58 new-field discoveries in 1983 with an average depth of 10,393 ft and a success rate of 22%. The 119 other exploratory discoveries in 1983 had a success rate of 73%. The Oligocene trend was the most active, with 43.9% of the wildcat drilling, followed by the Eocene trend. Offshore exploratory drilling slipped from 42 new-field wildcats in 1982 to 38 completed wildcats in 1983. Four new fields were discovered and 2 were extended. Average depth of an offshore exploratory well was 10,250 ft. With 61 wells listed as suspended operations at year end, the success rate of offshore exploratory wells could increase sharply. Onshore geophysical activity increased slightly in 1983 to 894 crew-weeks. Offshore activity hit an all-time high for the second year in a row with 288½ crew-weeks.

Oil and Gas Developments in Upper Gulf Coast of Texas in 1982

There were 2,412 wells drilled in the Upper Gulf Coast of Texas during 1982, a slight decrease (4%) from the 1981 total of 2,502. Onshore exploratory drilling decreased 14%, with 505 wildcats drilled in 1982 compared with 581 in 1981. Development drilling accounted for 79% of the total, with the 1,907 wells drilled in 1982 showing little change from the 1,918 development wells drilled in 1981. There were 55 new-field discoveries completed in 1982 with an average depth of 9,431 ft and a success rate of 18.5%. There were 134 other wildcat discoveries in 1982 with an average depth of 9,475 ft and a success rate of 64.7%. The Oligocene trend remained the most active, with 40.6% of the wildcats, followed by the Eocene trend with 34.6%. Most of the significant new-field discoveries were made in the Oligocene Frio and Eocene Wilcox Formations. After a 6-year low in offshore exploratory drilling in 1981 (42 wildcats), 1982 saw a solid rebound with 70 exploratory wells drilled. However, the success rate for new-field wildcats continued to fall (to 3.6%). Onshore geophysical activity hit a 4-year low in 1982 with only 872 crew-weeks worked. Offshore geophysical activity hit an all-time high in 1982 with 225 crew-weeks worked, probably in response to the 1983 expanded federal OCS sales.

Oil and Gas Developments in Upper Gulf Coast of Texas in 1981

Wells drilled in the Upper Texas Gulf Coast during 1981 totaled 2,502, up 37% from the 1980 total of 1,826. Onshore development drilling accounted for 76% of the total with 1,910 wells, a 36% increase over the previous year. Onshore exploratory drilling also had a 37% increase, with 581 wildcats drilled in 1981 compared with 420 wildcats drilled in 1980. There were 65 successful new-field discoveries in 1981 with an average depth of 10,549 ft and a success rate of 19.6%. The Oligocene trend remained the most active exploration trend with 44% of the wildcats; however, the Eocene trend, particularly the Yegua Formation, was the target of the most significant discoveries. Offshore, exploratory drilling decreased dramatically by 54% with only 42 wells drilled compared with 90 the previous year. Offshore development drilling increased 27% in 1981 with 88 wells drilled compared with 64 in 1980. Onshore, geophysical activity decreased slightly with 1,064 crew-weeks worked compared with 1,174 crew-weeks in 1980. Offshore geophysical activity also decreased with only 97.5 crew-weeks worked compared with the 156 crew-weeks of the previous year. In 2 state lease sales and 1 federal lease sale held in 1981, the industry spent $1.13 billion to acquire 476,530 acres.

Upper Gulf Coast of Texas

Wells drilled in the Upper Texas Gulf Coast during 1980 totaled 1,826, up over 35% from the previous year total of 1,344 and over 13% from the 1977 decade high of 1,584. Onshore development drilling accounted for most of the increase; activity was up 50% from 1979. Onshore exploratory drilling continued to climb, up from 406 wildcats in 1979 to 420 in 1980. Of these, 42% were in the Oligocene Trend, which remains the most actively explored trend in the coast. The onshore success rate was also up slightly, from 50 to 51 discoveries this year. Offshore exploratory drilling was on the rise in 1980, up 15%, while development drilling continued the 1978 decline trend, down 21% this year. Onshore geophysical activity totaled 1,174 crew weeks, up 224 from the 950 crew weeks in 1 79 and up 182 from the decade high of 992 in 1978. Offshore seismic activity increased to 156 crew weeks, a record high for the last 6 yr. In two state and one federal lease sales, the industry spent $1,480,820,025.03, acquiring 1,357,485.52 ac.

Developments in Upper Gulf Coast of Texas in 1979

Wells drilled in the Upper Texas Gulf Coast during 1979 totaled 1,351, a slight decline from the previous year's total of 1,540. The onshore Oligocene trend remained the most actively explored trend in 1979. A total of 406 exploratory wells was drilled resulting in 50 new-field discoveries. Onshore geophysical activity totaled 950 crew-weeks, keeping pace with the record high of 992 in 1978. The U.S. Department of Energy-sponsored geothermal/geopressure project well reached total depth and entered its 2-year testing phase. Offshore development drilling dropped 42% as did exploratory drilling which decreased 18% in 1979. In 2 state and 2 federal lease sales companies spent $327,361,042 leasing 494,953 acres.

Developments in Upper Gulf Coast of Texas in 1978

Wells drilled in the Upper Texas Gulf Coast during 1978 totaled 1,540, keeping pace with the decade high of 1,584 in 1977. The center of onshore development drilling shifted to the Cretaceous trend with extensive exploitation of the Austin Chalk. During 1978, 515 exploratory wells were drilled onshore resulting in 45 new-field discoveries. The Oligocene remained the most actively explored trend, accounting for most of the significant discoveries. Onshore seismic exploration increased by a staggering 83.8% with the largest increase reported in the northeast corner of the Cretaceous trend. The year also marked the beginning of the first geothermal geopressure project on the Upper Texas Gulf Coast. In addition, an enhanced oil recovery pilot was placed in operation at Manvel field. Offshore development drilling was down by 24%, but exploratory drilling reversed its 3-year decline. Only 2 offshore new-field discoveries were reported as operators held information confidential. In 2 federal and 2 state lease sales held in 1978, companies spent $401.4 million in acquiring 462,035 acres.

Developments in Upper Gulf Coast of Texas in 1977

Wells drilled in the Upper Texas Coast during 1977 totaled 1,584, an increase of 37% over 1976. Offshore development drilling increased 142% from 77 wells in 1976 to 186 in 1977, and onshore development activity was up 51.7%. During 1977, 532 exploratory wells were drilled onshore compared to 462 in 1976. The Oligocene was the most actively explored trend, accounting for most of the significant onshore discoveries. The Cretaceous-Jurassic trend showed a 67% increase in wildcat drilling over 1976. Additionally, seismic activity sharply increased in this trend. Offshore exploratory drilling continued its 3-year decline; however, significant discoveries were reported from Miocene and upper Oligocene rocks. It is estimated that the discovery of Shipwreck field (Galveston area will significantly increase offshore Texas gas reserves. In 1 federal and 3 state lease sales held in 1977, companies acquired 367,315 acres, predominantly bay and Gulf of Mexico tracts.