Red Snapper Distribution on Natural Habitats and Artificial Structures in the Northern Gulf of Mexico

In 2011, an intensive, multiple-gear, fishery-independent survey was carried out in the northern Gulf of Mexico (GOM) to collect comprehensive age and length information on Red Snapper Lutjanus campechanus. Based on this synoptic survey, we produced a spatial map of Red Snapper relative abundance that integrates both gear selectivity effects and ontogenetically varying habitat usage. Our methodology generated a spatial map of Red Snapper at a 10-km2 grid resolution that is consistent with existing knowledge of the species: Red Snapper occurred in relatively high abundances at depths of 50–90 m along the coasts of Texas and Louisiana and in smaller, patchy “hot spots” at a variety of depths along the Alabama coast and the west Florida shelf. Red Snapper biomass and fecundity estimates were higher for the northwestern GOM than for the northeastern GOM, as the latter area contained mostly smaller, younger individuals. The existence of similar surveys on petroleum platforms and artificial reefs also enabled us to calculate their relative contribution to Red Snapper distribution compared with that of natural habitats.We estimated that for the youngest ageclasses, catch rates were approximately 20 times higher on artificial structures than on natural reefs. Despite the high catch rates observed on artificial structures, they represent only a small fraction of the total area in the northern GOM; thus, we estimated that they held less than 14%of Red Snapper abundance. Because artificial structures—particularly petroleum platforms—attract mostly the youngest individuals, their contribution was even lower in terms of total population biomass (7.8%) or spawning potential (6.4%). Our estimates of Red Snapper relative abundance, biomass, and spawning potential can be used to design spatial management strategies or as inputs to spatial modeling techniques

Economic Costs of Historic Overfishing on Recreational Fisheries: South Atlantic & Gulf of Mexico Regions

Ocean fish are a vital renewable resource for human populations, providing food, employment, and recreation. Many fish stocks worldwide, however, are in a state of serious decline due to overfishing, environmental degradation, climate change, and other stressors. Fishing effort worldwide has remained relatively constant with only slight increases recorded, while the global production of marine fisheries has decreased (Food and Agriculture Organization of the United Nations, 2010). The South Atlantic and Gulf of Mexico regions of the United States have witnessed significant declines in fish stocks that are important to recreational and commercial fisheries. As of 2011, nine fish populations across the two regions were officially classified as "overfished." An additional 12 populations were classified as "subject to overfishing." Biological overfishing occurs when harvest rates from fishing exceed the growth rates of fish stocks. The resulting declines in fish populations can impact the economy at large. This study examines an important component of the costs of overfishing in the South Atlantic and Gulf of Mexico regions -- recreational catch losses from historic overfishing and their associated economic impacts. Our analysis covers nine federally managed overfished stocks in these two regions over the period 2005–2009, the most recent years for which the necessary data were available prior to the 2010 Deepwater Horizon oil spill in the Gulf. Those stocks are black sea bass, red grouper, red porgy, red snapper, and snowy grouper in the South Atlantic; and gag, gray triggerfish, greater amberjack, and red snapper in the Gulf of Mexico. Recreational fishing has long been an important economic activity in these regions. The money spent by recreational fishermen on charter fishing excursions, tackle, bait, fuel, and other expenses supports employment and economic activity across those regions. Our analysis assumes that recreational fisheries could have contributed more to regional economic activity had the stocks been capable of producing greater yields over the study period of 2005–2009. We estimate the size of the recreational catch loss for each species for each year and the economic activity that could have resulted had that catch been available. To arrive at our estimates of recreational catch loss, we compared average annual recreational harvests and effort for each stock for each year over the study period to potential estimated harvests and effort had the stocks been producing at optimum yield. We sourced our measures of optimum yield and maximum sustainable yield for each individual stock from regional stock assessments and fishery management plans. We valued the resulting catch loss by using data on trip expenditures by recreational fishermen in the South Atlantic and Gulf of Mexico. Effort and expenditure data were sourced from the Marine Recreational Fisheries Statistics Survey and includes trips that caught, targeted, or caught and/or targeted the stocks in our analysis.1 Economic multipliers were used to estimate the total direct, indirect, and induced economic activity that could have been generated by those recreational fishing expenditures. Our estimates of catch loss and associated economic impacts are not additive across stocks since trips and their respective expenditures may be associated with multiple stocks. Our analysis finds that recreational fisheries in the South Atlantic and Gulf of Mexico could have contributed millions of dollars more in additional recreational expenditures and associated economic activity had the fish species been producing at optimum yield over the study period. The greatest direct losses were associated with South Atlantic black sea bass and South Atlantic red snapper. Recreational fishermen in the South Atlantic spent $41.7 million on average annually to realize 44$52.8 million greater each year over the five-year study period had the stock been producing at optimum yield. An additional $52.8 million in recreational expenditures each year could have generated an additional$138 million in economic output and $40.3 million in income, and supported 896 jobs annually for the region. In the case of South Atlantic red snapper, fishermen spent$9.2 million on average annually over the study period to catch 37% of the recreational catch that could have been available under optimum yield. We estimate that recreational expenditures on South Atlantic red snapper could have been $15.9 million greater each year and could have contributed an additional$41.6 million in economic output and $12.2 million in income, and supported 270 jobs for the region annually between 2005–2009. In the Gulf region, the greatest losses were associated with red snapper, where recreational fishermen spent$22.4 million to realize 64% of the optimal catch that could have been available. We estimate that recreational expenditures on Gulf red snapper could have been $12.7 million greater each year had the stock been producing at optimum yield. An additional$12.7 million in recreational expenditures each year could have generated an additional $33.2 million in economic output and$9.7 million in income, and supported 215 jobs annually for the region. Our findings support the conclusion that overfished stocks can lead to significant economic losses for regional economies through forgone recreational fishing expenditures. This is only one component of the cost of overfishing. Our analysis does not estimate the value of catch losses in commercial fisheries or the broader impacts on ecosystems and biodiversity. The total value of catch losses resulting from historic overfishing would be greater still if other impacts had been considered. Despite these limitations, this study provides strong economic evidence in support of maintaining healthy ocean fish populations and continuing efforts to rebuild stocks currently subject to overfishing or classified as overfished

An Assessment of Montserrat's Fisheries

This report provides an assessment of Montserrat's fisheries, and includes an estimate of the status of six species targeted by the fishery

The ecological basis of fishery yield of the Puerto Rico-Virgin Islands Insular Shelf: 1987 Assessment

A literature review was conducted to locate information on the flow of energy from primary producers to the fishery stocks of the Puerto Rican-Virgin Islands insular shelf. This report uses site-specific information to describe the major ecological subsystems, or habitats, of the region, to identify the more common species and the subsystems in which they occur, to quantify productivity and biomass, and to outline trophic relationships. Discussions on each topic and subsystem vary in substance and detail, being limited by the availability and accessibility of information. (PDF contains 189 pages) Seven distinct subsystems are described: mangrove estuary, seagrass bed, coral reef, algal plain, sand/mud bottom, shelf break, and overlying pelagic. Over 50 tables provide lists of species found in each habitat on various surveys dating back to 1956. Estimates of density, relative abundance, and productivity are provided when possible. We evaluated whether sufficient information exists to support an analysis of the energy basis of fishery production in the area, beginning with the design and development of an ecosystem model. Data needs in three categories - species lists, biomass, and trophic relations - were examined for each subsystem and for each of three species groups - primary producers, invertebrates, and fish. We concluded that adequate data, sufficient for modeling purposes, are available in 16 (25%) of 64 categories; limited data, those requiring greater extrapolation, are available in 35 (55%) categories; and no data are available in 13 (20%) categories. The best-studied subsystems are seagrass beds and coral reefs, with at least limited data in all categories. Invertebrates, the intermediate link in the food web between primary producers and fishes, are the least quantified group in the region. Primary production and fishes, however, are relatively well-studied, providing sufficient data to support an ecosystem-level analysis and to initiate a modeling effort

The Hidden Cost of Overfishing To Commercial Fishermen: A 2009 Snapshot of Lost Revenues

Ocean fish populations are a vital renewable resource for human populations, providing food,employment and recreation, as well as contributing to global biodiversity. Unfortunately, due to overfishing, environmental degradation, climate change and other stressors, many fish stocks worldwide are in considerable decline.Biological overfishing occurs when fishing rates exceed population growth rates. The resulting declines in fish populations can impact the economy at large. This study analyzes one important component of the costs of overfishing: forgone revenues from lost commercial fisheries harvests due to years of continuedstock depletion, or historic overfishing. It estimates the present annual forgone revenue of overfishing for three regions in the United States: New England, the South Atlantic and the Gulf of Mexico. These regions were chosen for analysis because they are grappling with the effects of historic overfishing and therefore have a significant number of overfished stocks. The 20 stocks included in this analysis are federally managed stocks particular to each region that are included in the Fish Stock Sustainability Index and are currently classified by the National Marine Fisheries Service as "overfished." A stock that is classified as overfished is defined as having a biomass level below a biological threshold specified in its fishery management plan.Overfishing means fewer fish are available to catch in future years. The annual forgone revenue of historic overfishing, therefore, is an estimate of the value of lost catch in a given year due to overfishing. To arrive at the catch loss for each fishery, we first estimated the potential landings of each overfished stock as if it were at healthy levels, and compared those estimates directly to current landings values. We measured potential landings for each fish stock on the basis of optimal yield, and examined four approximations of optimal yield. Our estimates of commercial catch losses are for 2009, the most recent year for which all necessary data were available.Based on our estimates, the aggregate catch loss summed over all three regions in 2009 was $164.2 million. Under a less-conservative approximation of optimal yield, commercial catch loss across all three regions in 2009 was estimated at$222.5 million. Across all three regions, we demonstrated that only 20 to 29 percent of potential landings in 2009 were realized in actual landings. We found the commercial catch loss ($149 million) to be greatest in New England, where there are more overfished species than in any other region in the United States. In the Gulf of Mexico and South Atlantic regions, where large catch allocations are apportioned to recreational fishing, and therefore not accounted for in this analysis, commercial catch losses were lower but still significant. Commercial catch loss in the Gulf of Mexico and the South Atlantic regions were$12.3 million and $2.9 million, respectively.Our estimates of losses resulting from historic overfishing apply to commercial landings only, and do not account for the backward-linked economic impacts of commercial harvest, nor the forward-linked economic activity that would have resulted from the processing and retail sale of these potential catches. Additionally, there are further economic losses beyond the commercial sector in other industries, such as recreational fishing, and there are costs associated with negative impacts to food security, biodiversity and other ecosystem services that are not addressed in this analysis. Commercial catch losses are onesignificant component of the total economic costs of overfishing. Estimates of commercial catch loss we find in this study provide a strong economic argument in support of maintaining healthy fish populations and avoiding delays in rebuilding stocks currently subject to overfishing and/or classified as overfished.

Structural Vector Error Correction Modeling of Integrated Sportfishery Data

We demonstrate how to specify and estimate a time series model that can isolate the effects of changes in fishery policy and forecast the outcome of policy changes in the context of changing climate and economic factors. The approach is illustrated with data from the headboat fishery for red snapper in the Gulf of Mexico. The initial data analysis finds that effort and harvest are cointegrated series and that effort appears to respond somewhat to past changes in harvest. This suggested a structural vector error correction model specification. Model estimation results indicate that seasonal closures directly influence both harvest and effort, whereas bag and minimum size limits only affect harvest directly. Also, climate activity has a moderate influence on this fishery, mainly via changes in effort. Model forecasts are evaluated relative to a more naïve specification using out-of-sample data and the use of the model for policy analysis is demonstrated.Climate, Gulf of Mexico, red snapper, sportfishing demand, structural vector error correction, time series, Public Economics, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy, Risk and Uncertainty, Q22 Q26 Q28 C32,

Habitat connectivity in reef fish communities and marine reserve design in Old Providence-Santa Catalina, Colombia

On the insular platform of Old Providence/Santa Catalina, Colombia, we compared nearshore lagoonal patch reefs to those on the northern bank distant from the islands to determine the importance of habitat connectivity to fish community structure. Nearshore patch reefs had greater proximity to mangrove, seagrass and rocky shore habitats, and they had significantly more individuals. Nearshore reefs also tended to have a greater total biomass, more species, a higher proportion of predators of mobile invertebrates and small fishes, and a lower proportion of herbivores. Biomass of snappers and grunts at nearshore sites was four times greater compared to bank sites, and was correlated with the amount of seagrass and sand/rubble habitat within 500 m of each patch reef. We also compared length-frequency distributions and abundances of grunts and snappers among all sites (deep and shallow forereefs, patch reefs and deep and shallow leeside slopes). The results were consistent with ontogenetic migrations from shallow sites, primarily seagrass and mangrove habitats, to deeper sites and to those further out on the bank. The evidence suggests that species differed in both distance and direction of dispersal, which may be affected by the abundance and distribution of preferred habitats. Marine reserves near the islands should target nearshore nursery areas and patch reefs harboring species of limited dispersal capability. Reserves on the northern bank would protect spawners of those species showing the greatest dispersal capability

A comparison of size and age of red snapper (Lutjanus campechanus) with the age of artificial reefs in the northern Gulf of Mexico

Despite extensive study, it still is not clear whether artificial reefs produce new fish biomass or whether they only attract various species and make them more vulnerable to fishing mortality. To further evaluate this question, the size and age of red snapper (Lutjanus campechanus) were sampled from April to November 2010 at artificial reefs south of Mobile Bay off the coast of Alabama and compared with the age of the artificial reef at the site of capture. Red snapper were collected with hook and line and a fish trap and visually counted during scuba-diver surveys. In the laboratory, all captured red snapper were weighed and measured, and the otoliths were removed for aging. The mean age of red snapper differed significantly across reefs of different ages, with older reefs having older fish. The mean age of red snapper at a particular reef was not related to reef depth or distance to other reefs. The positive correlation between the mean age of red snapper and the age of the reef where they were found supports the contention that artificial reefs in the northern Gulf of Mexico enhance production of red snapper. The presence of fish older than the reef indicates that red snapper are also attracted to artificial reefs

An Ecopath with Ecosim Analysis on Offshore Petroleum Platform Influences on Gulf of Mexico Red Snapper

Offshore oil and gas platforms have had a significant presence in the Gulf of Mexico since the 1950s. An important secondary function of these structures is that they provide artificial habitat to fisheries, most notably Red snapper. Policy changes intended to reduce the risk associated with aging infrastructure have reduced the number of standing platforms from 4044 to 1867 from 2001 to 2018. The effect this loss of habitat has on Red snapper was tested by creating three scenarios of platform changes and modeling the perturbation from 2005 to 2050. The simulation was accomplished using the ecological model Ecopath with Ecosim (EwE) where Ecosim executes the time dynamic portion of the model and Ecopath provides the initial mass balanced information for all species in the system. Fecundity estimates were used on a per platform basis and imposed on the egg production parameter of the Ecosim model to complete the scenarios. Results showed Red snapper fecundity on platforms to be relatively low resulting in minor changes in biomass for all three scenarios of offshore platform change. The most notable differences were in the types of vulnerability estimations used which dictates the interaction between organisms in the model. Based on these parameters offshore platforms were not seen to be a major contributor to Red snapper populations in any scenario or estimation method

Use of a Simple Age-Structured Bioeconomic Model to Estimate Optimal Long-Run Surpluses

When the New Zealand government introduced individual transferable quotas for major commercial fish stocks, the initial allocation for some stocks exceeded their total allowable catches and made it necessary to buy back immediately some of the quota. Quota was offered back by tender. A simple age-structured bioeconomic model was used to estimate long-run optimal surpluses. From these, the maximum prices that should be paid by government for quota were derived. The use of an age-structured model proved convenient for this purpose as the necessary parameter estimates tend to arise naturally from literature sources and the population dynamics are transparent. If stocks were managed optimally, the long-run value of quota would be equivalent to the net present value of the surplus at the dynamic maximum economic yield. Long-run surpluses proved to be dependent on the relative changes in catch rates and costs of fishing which resulted from changes in stock biomass. Optimal surpluses of up to 45% of the greenweight revenues were obtained for heavily exploited, long-lived stocks. Only small long-run surpluses were obtained for short-lived or very lightly exploited stocks.Environmental Economics and Policy, Resource /Energy Economics and Policy,