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At least 1,405 records · Page 78Linked to original sources

USGS2019

Early mortality and freshwater forage fish recruitment: Nonnative alewife and native rainbow smelt interactions in Lake Champlain

We studied the consequences of a nonnative species introduction and changes in temperature on early mortality and recruitment of native rainbow smelt ( Osmerus mordax ) and nonnative alewife ( Alosa pseudoharengus ) in Lake Champlain using a simulation model. Distribution patterns of adults and young-of-the-year (YOY) fish were predicted using a model based on observed distribution of different age groups as a function of temperature and light profiles simulated on a daily basis. Mortality rates averaged over the growing season were calculated as a function of fish densities and overlap between adults and YOY. Survival of YOY rainbow smelt and alewife depended on which predator was most abundant. Rainbow smelt YOY mortality rates are highest when rainbow smelt adults are abundant, and alewife YOY mortality rates are highest when alewife adults are abundant, potentially allowing coexistence. August and September mortality rates were higher in the climate change scenario because of increased overlap of adults and YOY of both species. These results indicate that accounting for spatiotemporal fish distribution patterns can be important when forecasting the interacting effects of climate change and aquatic invasive species on fish recruitment.

New York, Quebec, Vermont↗

USGS2020

Remarkable response of native fishes to invasive trout suppression varies with trout density, temperature, and annual hydrology

Recovery of imperiled fishes can be achieved through suppression of invasives, but outcomes may vary with environmental conditions. We studied the response of imperiled desert fishes to an invasive brown ( Salmo trutta ) and rainbow trout ( Oncorhynchus mykiss ) suppression program in a Colorado River tributary, with natural flow and longitudinal variation in thermal characteristics. We investigated trends in fish populations related to suppression and tested hypotheses about the impacts of salmonid densities, hydrologic variation, and spatial–thermal gradients on the distribution and abundance of native fish species using zero-inflated generalized linear mixed effects models. Between 2012 and 2018, salmonids declined 89%, and native fishes increased dramatically (∼480%) once trout suppression surpassed ∼60%. Temperature and trout density were consistently retained in the top models predicting the abundance and distribution of native fishes. The greatest increases occurred in warmer reaches and in years with spring flooding. Surprisingly, given the evolution of native fishes in disturbance-prone systems, intense, monsoon-driven flooding limited native fish recruitment. Applied concertedly, invasive species suppression and efforts to mimic natural flow and thermal regimes may allow rapid and widespread native fish recovery.

Arizona↗

USGS2010

Environmental drivers of fish functional diversity and composition in the Lower Colorado River Basin

Freshwater conservation efforts require an understanding of how natural and anthropogenic factors shape the present-day biogeography of native and non-native species. This knowledge need is especially acute for imperiled native fishes in the highly modified Lower Colorado River Basin (LCRB), USA. In the present study we employed both a taxonomic and functional approach to explore how natural and human-related environmental drivers shape landscape-scale patterns of fish community composition in the LCRB. Our results showed that hydrologic alteration, watershed land use, and regional climate explained 30.3% and 44.7% of the total variation in fish community taxonomic and functional composition, respectively. Watersheds with greater dam densities and upstream storage capacity supported higher non-native functional diversity, suggesting that dams have provided additional "niche opportunities" for non-native equilibrium life-history strategists by introducing new reservoir habitat and modifying downstream flow and thermal regimes. By contrast, watersheds characterized by greater upstream land protection, lower dam densities, and higher variation in spring and summer precipitation supported fish communities with a strong complement of native species (opportunistic-periodic strategists). In conclusion, our study highlights the utility of a life-history approach to better understand the patterns and processes by which fish communities vary along environmental gradients.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2012

Pacific salmon (Oncorhynchus spp.) runs and consumer fitness: growth and energy storage in stream-dwelling salmonids increase with salmon spawner density

We examined how marine-derived nutrients (MDN), in the form of spawning Pacific salmon, influenced the nutritional status and δ 15 N of stream-dwelling fishes. We sampled juvenile coho salmon ( Oncorhynchus kisutch ) and Dolly Varden ( Salvelinus malma ) during spring and fall from 11 south-central Alaskan streams that ranged widely in spawning salmon biomass (0.1–4.7 kg·m –2 ). Growth rate (as indexed by RNA–DNA ratios), energy density, and δ 15 N enrichment in spring-sampled fishes increased with spawner biomass, indicating the persistence of spawner effects more than 6 months after salmon spawning. Point estimates suggest that spawner effects on nutrition were substantially greater for coho salmon than Dolly Varden (268% and 175% greater for growth and energy, respectively), indicating that both species benefitted physiologically, but that juvenile coho salmon accrued more benefits than Dolly Varden. Although the data were less conclusive for fall- than spring-sampled fish, they do suggest spawner effects were also generally positive during fall, soon after salmon spawned. In a follow-up analysis where growth rate and energy density were modeled as a function of δ 15 N enrichment, results suggested that both increased with MDN assimilation, especially in juvenile coho salmon. Our results support the importance of salmon runs to the nutritional ecology of stream-dwelling fishes.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS1973

Computer program for sample sizes required to determine disease incidence in fish populations

A computer program is described for generating the sample size tables required in fish hatchery disease inspection and certification. The program was designed to aid in detection of infectious pancreatic necrosis (IPN) in salmonids, but it is applicable to any fish disease inspection when the sampling plan follows the hypergeometric distribution.

Journal of the Fisheries Research Board of Canada↗

USGS1991

Downstream effects of mine effluent on an intermontane riparian system

Metal concentrations were determined in benthic biota, fish livers, water, and fine-grained sediment through 215 km of an intermontane river system (Blackfoot River, Montana, USA) affected by headwater inputs of acid-mine effluent. Solute and particulate contaminants decreased rapidly downstream from headwater sources, but some extended through an extensive marsh system. Particulate contaminants penetrated through the marsh system, effectively resulting in food web contamination downstream of the marshes. Metals differed in their bioavailability within and below the marsh system. Cadmium was most consistently accumulated in the food web, and the general order of downstream mobilization of bioavailable metals appears to be Cd, Zn > Cu > As, Ni. Depauperate benthic communities and reduced fish populations occurred coincident with the sediment contamination.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS1946

Relative toxicity of suspension and oil formulations of DDT to native fishes in Back Creek, West Virginia

On July 23, 1947, a 1‐mile section of Back Creek, treated the previous year with a DDT suspension with little damage to fish, was re‐treated with an oil spray at the same rate (1 pound per acre). The oil spray killed about six times as many fish as the suspension formula. Fish began dying within 3 to 4 hours after treatment, whereas several days elapsed before mortality began with the suspension formula in 1946. In addition to larger numbers of the minnow species, some adult game fish were killed. Losses of fish were not as great below the sprayed section as when a suspension formula was used, probably because a good part of the DDT was drifted ashore by breezes or by water currents. Some species of fish such as bluntnose minnows (Hyborhynchus notatus), chub suckers (Erimyzon oblongus), and pickerel (Esox niger), although numerous, were relatively unaffected. Considerable mortality of largemouth bass (Micropterus salmoides) and bluegill sunfish (Lepomis macrochirus) occurred in liveboxes placed in the sprayed section, particularly at the lower stations. Largemouth bass nearly 4 inches long survived at a station where 54.0 percent of the 2‐inch bass were killed. This fact supplied some positive evidence that fish of larger size are better able to withstand DDT.

West Virginia↗

USGS1985

Toxic materials, fishing, and environmental variation: Simulated effects on striped bass population trends

Decreased survival of larval striped bass Morone saxatilis resulting from toxic chemicals in the environment and decreased survival of adults caused by fishing both are suspected as agents contributing to the decline in the Chesapeake Bay stock since the mid‐1970s. The relative power of each type of mortality to cause population declines was evaluated with simulation techniques. Equivalent levels of added mortality induced qualitatively identical and quantitatively similar trends in population simulations for all conditions examined except if strong density‐dependent mortality preceded the contaminant toxicity. In this case the contaminant effect caused a greater reduction in yield, but the population did not tend toward extinction. The results indicate that the observed downward trend in the Chesapeake Bay population can be halted or reversed by a reduction in fishing mortality, even if contaminant toxicity is the proximate cause for the decline.

Maryland↗

USGS2003

Hankin and Reeves' approach to estimating fish abundance in small streams: Limitations and alternatives

Hankin and Reeves' (1988) approach to estimating fish abundance in small streams has been applied in stream fish studies across North America. However, their population estimator relies on two key assumptions: (1) removal estimates are equal to the true numbers of fish, and (2) removal estimates are highly correlated with snorkel counts within a subset of sampled stream units. Violations of these assumptions may produce suspect results. To determine possible sources of the assumption violations, I used data on the abundance of steelhead Oncorhynchus mykiss from Hankin and Reeves' (1988) in a simulation composed of 50,000 repeated, stratified systematic random samples from a spatially clustered distribution. The simulation was used to investigate effects of a range of removal estimates, from 75% to 100% of true fish abundance, on overall stream fish population estimates. The effects of various categories of removal-estimates-to-snorkel-count correlation levels (r = 0.75-1.0) on fish population estimates were also explored. Simulation results indicated that Hankin and Reeves' approach may produce poor results unless removal estimates exceed at least 85% of the true number of fish within sampled units and unless correlations between removal estimates and snorkel counts are at least 0.90. A potential modification to Hankin and Reeves' approach is the inclusion of environmental covariates that affect detection rates of fish into the removal model or other mark-recapture model. A potential alternative approach is to use snorkeling combined with line transect sampling to estimate fish densities within stream units. As with any method of population estimation, a pilot study should be conducted to evaluate its usefulness, which requires a known (or nearly so) population of fish to serve as a benchmark for evaluating bias and precision of estimators.

Transactions of the American Fisheries Society↗

USGS1996

Establishment of a fish community in the Hayden-Rhodes and Salt-Gila aqueducts, Arizona

Fish populations were studied in the Central Arizona Projectˈs canal system during the first 4 years of aqueduct operation (1986–1989). Ichthyoplankton entering the canal from Lake Havasu averaged 1 larva/m 3 during April–June 1987 and 1988. Larval fish densities increased significantly in downstream samples, substantiating diver observations that fish were spawning in the canal system. Of the 16 fish species collected, 14 were assumed to have originated from Lake Havasu and 2 were introduced by anglers from their bait buckets. Initially, the fish community was dominated numerically by threadfin shad Dorosoma petenense (>88%), centrarchids (< 10%), cyprinids (<2%), and striped bass Morone saxatilis (<I%). However, as annual water diversions increased from 1.3 × 10 8 m 3 in 1986 to 9.4 × 10 8 m 3 in 1989, community composition shifted from clupeids to centrarchids (70%). Fish densities dropped from an estimated 1,260 fish/ha in 1986 to 17 fish/ha in 1989, and biomass dropped from 116 to 73 kg/ha. Declines were attributed to higher operational velocities, associated scour, deprivation, and predation. Although initial populations adjusted downward to planned operational conditions, the fish community continued to represent a potentially valuable, but as yet unused, resource.

Arizona↗

USGS2005

Laboratory studies on the vulnerability of young white sturgeon to predation

Despite evidence of annual spawning by white sturgeon Acipenser transmontanus in rivers of the northwestern United States and Canada, in some years and locations little or no recruitment of age-0 white sturgeon has been observed. We examined the vulnerability of white sturgeon larvae and juveniles to predation to further understand possible causes of mortality. We were particularly interested in the vulnerability of older larvae and juveniles because at about 25 mm total length (TL) white sturgeon develop sharp dorsal and lateral scutes that may act as a morphological defense. In the laboratory, white sturgeon ranging from newly hatched larvae to about 170-mm TL juveniles were exposed to predatory fishes they might encounter in the natural environment. We found that channel catfish Ictalurus punctatus (mean TL = 464 mm) and northern pikeminnow Ptychocheilus oregonensis (mean TL = 472 mm) ate white sturgeon up to mean sizes of 121 and 134 mm TL, respectively. Conversely, similarly sized walleyes Sander vitreus ingested almost no white sturgeon, although juvenile walleyes (mean TL = 184 mm) ate white sturgeon up to 59 mm TL. The smallest predator we tested, prickly sculpins Cottus asper (mean TL = 126 mm), ate white sturgeon up to a mean TL of 50 mm. Our study demonstrated that predation is a likely cause of mortality of age-0 white sturgeon and may be contributing to the year-class failures that have been observed. In addition, the results from this study could be used to reduce the predation risk of artificially propagated white sturgeon released to augment declining populations since fish could be reared to sizes where their vulnerability is low.

North American Journal of Fisheries Management↗

USGS1999

Modeling data from double-tagging experiments to estimate heterogeneous rates of tag shedding in lake trout (Salvelinus namaycush)

Data from mark-recapture studies are used to estimate population rates such as exploitation, survival, and growth. Many of these applications assume negligible tag loss, so tag shedding can be a significant problem. Various tag shedding models have been developed for use with data from double-tagging experiments, including models to estimate constant instantaneous rates, time-dependent rates, and type I and II shedding rates. In this study, we used conditional (on recaptures) multinomial models implemented using the program SURVIV (G.C. White. 1983. J. Wildl. Manage. 47: 716-728) to estimate tag shedding rates of lake trout (Salvelinus namaycush) and explore various potential sources of variation in these rates. We applied the models to data from several long-term double-tagging experiments with Lake Superior lake trout and estimated shedding rates for anchor tags in hatchery-reared and wild fish and for various tag types applied in these experiments. Estimates of annual tag retention rates for lake trout were fairly high (80-90%), but we found evidence (among wild fish only) that retention rates may be significantly lower in the first year due to type I losses. Annual retention rates for some tag types varied between male and female fish, but there was no consistent pattern across years. Our estimates of annual tag retention rates will be used in future studies of survival rates for these fish.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2024

Assessing habitat use and population dynamics of fisheries resources at Kaloko Fishpond

Throughout Hawai'i, fishponds are considered by their local communities as important cultural touchstones, a source of local, sustainably produced food, and an important component to the development of community-based management for nearshore fisheries. Within Kaloko-Honokōhau National Historical Park, the restoration of Kaloko Fishpond for traditional aquaculture management is a goal of both the National Park Service (NPS) and Hui Kaloko-Honokōhau, a community-based group of kia'i, i.e., caretakers and native Hawaiian cultural practitioners. However, existing data on the demographics and condition of the fish populations within the pond, and the fish-habitat quality are poor to non-existent. Therefore, the objectives of this study were to: catalog fish species composition and distribution in the pond; estimate the abundance of focal species/taxonomic groups; and evaluate the occupancy patterns of the invasive algae Acanthophora spicifera and Upside-down Jellyfish Cassiopea andromeda. As part of these objectives, a survey protocol and analysis framework were designed and evaluated to ensure that the NPS and community group would be able to refine and implement them to continue their monitoring efforts. We conducted dual-observer shore-based visual surveys multiple times per week during September-October 2020 and April-September 2022. A total of 41 species/taxonomic groups were recorded over the course of the surveys. The largest number of species/taxonomic groups were observed at survey stations located on or near the kuapā, or wall separating the fishpond from the ocean. N-mixture models fitted to the data estimated a total population of 353 – 392 mullets, 134 – 192 flagtails (āholehole), and 189 – 277 Milkfish (Awa) Chanos chanos occurring within the 1.2-ha portion of Kaloko Fishpond that could be surveyed visually from the shoreline. Multi-season occupancy models fitted to the surveyed presence of A. spicifera and Upside-down Jellyfish indicted sites throughout most of the pond exhibited moderate and consistent occupancy (ψ = 0.30 – 0.40) throughout much of the pond, except for the northeast corner of the pond (Kaloko Iki) where colonization rates were lower and extinction rates higher than other areas within Kaloko. The visual survey method developed for this study provides a low-cost and effective starting point for the development of methodology that can be used both by NPS personnel and volunteers from the community group. However, we were only able to estimate fish populations for approximately 24% of the area of Kaloko Fishpond with this method. Given that the deeper areas of Kaloko Fishpond are completely inaccessible to the visual survey method used, generating population estimates for the entire pond based on the parameters estimated in the current study is not recommended without further investigation into fish movement and habitat use. Various means to refine this protocol to better meet the needs and abilities of the NPS and community group are proposed.

Hawaii↗

USGS2021

Habitat suitability index model improvement recommendations

As part of the model improvement effort for the 2023 Coastal Master Plan, the Habitat Suitability Index (HSI) models used during previous master plans were reevaluated to assess how the model relationships could be improved, and to determine what species should be included in the master plan analyses. This process considered the technical reviews, comments, and suggested improvements provided by model developers, advisory groups, and other experts during previous master plans. Reviews were then conducted to determine the availability of data and information that could be used to make model improvements. As a result of this effort, a recommended list of relevant species to model is provided, and HSI model improvements are recommended that are categorized by whether the suitability index (SI) relationship to be improved is statistical-based or literature-based. The species recommended to be included in the 2023 Coastal Master Plan analyses are: eastern oyster, brown shrimp, white shrimp, blue crab, crayfish, gulf menhaden, spotted seatrout, largemouth bass, American alligator, gadwall, mottled duck, brown pelican, seaside sparrow, and bald eagle. These species were selected because they represent a range of taxonomies, life histories, trophic levels, and habitats, and most are commercially- or recreationally-important in coastal Louisiana. Most of these species were also included in the 2017 Coastal Master Plan analyses, and the models used during that effort should be further improved. Seaside sparrow and bald eagle are new for the master plan, and new models should be developed for the analyses. The 2017 fish, shrimp, and blue crab HSI models included a water quality SI that was based on statistical analyses of species catch and environmental data collected by the Louisiana Department of Wildlife and Fisheries. As suggested during the 2017 Coastal Master Plan, the modeling approach used to develop the water quality SI was revisited and alternate modeling approaches were explored. Using literature and an evaluation of the general steps of model development, three components for HSI model improvement were identified, including 1) selecting alternative modeling approach(es); 2) detecting and resolving statistical issues; and 3) improving model fit and evaluation. Multiple options for each component were explored, which resulted in a proposed multi-step phased approach for model improvement. This proposed approach entails improving the generalized linear models used for the 2017 water quality SIs and then, if desired, comparing them to alternative model approaches (e.g., generalized additive models) to explore model performance and select the best approach to use for the 2023 Coastal Master Plan HSI models. All of the existing master plan HSI models include literature-based SIs, which use information from published studies of species-habitat associations to derive suitability relationships. Similar to previous master plans, these literature-based SIs should be updated and improved for the 2023 Coastal Master Plan using recent literature and new ecological knowledge. Preliminary reviews were conducted and recent information was found that could be used to improve the eastern oyster, crayfish, and potentially brown pelican HSI models; but no appropriate recent literature was located for improvement of the American alligator, gadwall, and mottled duck HSI models. However, it is recommended that the literature reviews and information searches be continued. In addition to the statistical-based water quality SI, the 2017 fish, shrimp, and blue crab HSI models also included a structural habitat SI that was based on literature showing high densities of these species in fragmented marsh. The relationship used for this SI, however, did not account for the effects of other estuarine habitats, such as submerged aquatic vegetation and oyster reefs, which are also important to these species. Therefore, a meta-analysis approach is proposed that would estimate the relative importance of these habitats for each species, and the results of this analysis could be used to calculate a new structural habitat SI for the 2023 Coastal Master Plan.

Report↗

USGS2020

North Atlantic right whale (Eubalaena glacialis) scenario planning summary report

Scenario planning provides a structured framework that can be used in strategic planning to help manage risk and prioritize actions (Schwartz 1996; Peterson et al. 2003). By providing a mechanism to communicate about complex situations, scenario planning encourages “out-of-the-box” thinking to help groups assess the impacts of plausible future scenarios on a target or resource. The outcomes from scenario planning can be used to improve management decisions, highlight data gaps, and/or identify future science priorities (Star et al. 2015; Borggaard et al. 2019). The application of scenario planning by resource management organizations (e.g., Borggaard et al. 2019; Runyon et al. 2020; Star et al. 2015) and the urgency surrounding the recovery of the critically endangered North Atlantic right whale (Eubalaena glacialis), led to a 2018 NOAA Fisheries scenario planning initiative for the species. In addition to complementing the many management and conservation efforts already underway, this initiative was designed to address the uncertainties around future anthropogenic and environmental changes and how these uncertainties may impact species recovery. We used a scenario planning framework to explore plausible future conditions for North Atlantic right whales and to develop possible options to address those conditions and improve recovery. Specific objectives were to: 1) better understand the challenges of right whale management in a changing climate; 2) identify potential research activities and recovery needs across the species’ range; 3) increase coordination and collaboration related to recovery efforts; and 4) explore how scenario planning can be used to support decisions. Using projected changes in ocean conditions coupled with anthropogenic stressors, we built four plausible future scenarios for right whales. These scenarios helped identify priority research and management actions that NOAA Fisheries and our partners can undertake to improve right whale recovery. We identified priority actions related to science, management, and partnerships including, but not limited to, 1) research on shifting spatial and temporal distributions of right whales and prey in a changing climate; 2) development of technology to further reduce impacts from human activities; 3) continuation of ongoing management efforts related to vessel traffic and fishing; and 4) continued maintenance of existing and development of new partnerships (e.g., industry engagement in problem solving). This scenario planning exercise helped prioritize North Atlantic right whale management and science needs in light of changing ocean conditions and anthropogenic impacts. It can also serve as a reference for how NOAA Fisheries and its partners can better prepare for multiple plausible futures while complementing other on-going initiatives. Priorities identified here can be considered in conjunction with implementation and monitoring actions such as with the Atlantic Large Whale Take Reduction Team (ALWTRT) and/or regional Right Whale U.S. Implementation Teams. The framework can also be repeated and improved upon as additional information becomes available to support future exercises.

Technical Memorandum↗

USGS1991

A modeling assessment of the thermal regime for an urban sport fishery

Water temperature is almost certainly a limiting factor in the maintenance of a self-sustaining rainbow trout ( Oncorhynchus mykiss , formerly Salmo gairdneri ) and brown trout ( Salmo trutta ) fishery in the lower reaches of the Cache la Poudre River near Fort Collins, Colorado, USA. Irrigation diversions dewater portions of the river, but cold reservoir releases moderate water temperatures during some periods. The US Fish and Wildlife Service’s Stream Network Temperature Model (SNTEMP) was applied to a 31-km segment of the river using readily available stream geometry and hydrological and meteorological data. The calibrated model produced satisfactory water temperature predictions (R 2 =0.88, P <0.001, N=49) for a 62-day summer period. It was used to evaluate a variety of flow and nonflow alternatives to keep water temperatures below 23.3°C for the trout. Supplemental flows or reduced diversions of 3 m 3 /sec would be needed to maintain suitable summer temperatures throughout most of the study area. Such flows would be especially beneficial during weekends when current irrigation patterns reduce flows. The model indicated that increasing the riparian shade would result in little improvement in water temperatures but that decreasing the stream width would result in significant temperature reductions. Introduction of a more thermally tolerant redband trout ( Oncorhynchus sp.), or smallmouth bass ( Micropterus dolomieui ) might prove beneficial to the fishery. Construction of deep pools for thermal refugia might also be helpful.

Environmental Management↗

USGS2009

A comparison of complete mitochondrial genomes of silver carp hypophthalmichthys molitrix and bighead carp hypophthalmichthys nobilis: Implications for their taxonomic relationship and phylogeny

Based upon morphological characters, Silver carp Hypophthalmichthys molitrix and bighead carp Hypophthalmichthys nobilis (or Aristichthys nobilis) have been classified into either the same genus or two distinct genera. Consequently, the taxonomic relationship of the two species at the generic level remains equivocal. This issue is addressed by sequencing complete mitochondrial genomes of H. molitrix and H. nobilis, comparing their mitogenome organization, structure and sequence similarity, and conducting a comprehensive phylogenetic analysis of cyprinid species. As with other cyprinid fishes, the mitogenomes of the two species were structurally conserved, containing 37 genes including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA (tRNAs) genes and a putative control region (D-loop). Sequence similarity between the two mitogenomes varied in different genes or regions, being highest in the tRNA genes (98??8%), lowest in the control region (89??4%) and intermediate in the protein-coding genes (94??2%). Analyses of the sequence comparison and phylogeny using concatenated protein sequences support the view that the two species belong to the genus Hypophthalmichthys. Further studies using nuclear markers and involving more closely related species, and the systematic combination of traditional biology and molecular biology are needed in order to confirm this conclusion. ?? 2009 The Fisheries Society of the British Isles.

Journal of Fish Biology↗

USGS2011

Groupers on the edge: Shelf edge spawning habitat in and around marine reserves of the northeastern Gulf of Mexico

The northeastern Gulf of Mexico contains some of the most diverse and productive marine habitat in the United States. Much of this habitat, located on the shelf edge in depths of 50 to 120 m, supports spawning for many economically important species, including groupers. Here, we couple acoustic surveys with georeferenced videography to describe the primary spatial and geologic features of spawning aggregation sites for four economically important species: gag ( Mycteroperca microlepis ), scamp ( M. phenax ), red grouper ( Epinephelus morio ), and red snapper ( Lutjanus campechanus ), with notes on fish distribution and abundance and spawning activities. We provide information on movement patterns of reef fish determined using acoustic telemetry. Finally, we discuss the possible coupling of geomorphology with hydrographic features to influence the overall productivity of the region and the importance of spatial fishery management in sustaining that productivity.

Northeastern Gulf of Mexico↗