90 research outputs found

    Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest): Black, green, and red abalones

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    All abalones belong to the genus Haliotis sensu latu, family Haliotidae. The 75 species known worldwide (Booloot ian et, al. 1962) are anatomically similar and all are adapted for attachment to hard substrates. Seven species are widely distributed along the coast of California (Cox 1962; Mottet 19781, of which several are important in the comercial and sport fisheries of the Pacific Southwest. (PDF has 19 pages.

    Regional differences in an established population of invasive Indo-Pacific lionfish (Pterois volitans and P. miles) in south Florida

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    About nine years ago (circa 2009), Indo-Pacific lionfishes (Pterois volitans and P. miles) invaded the south Florida coral reef ecosystem. During the intervening period of time, there has been substantial research on their biology, life history, demography, and habitat preferences; however, little is known concerning their regional population status and trends in the region. Here, we use a large-scale fisheries independent reef fish visual survey to investigate lionfish population status among three south Florida regions: Dry Tortugas, Florida Keys, and southeast Florida. Density estimates (ind ha−1) have been relatively stable since 2012, and are lower than other areas reported in the western Atlantic and Caribbean Sea. Low, stable population densities in south Florida suggest there may be a natural mechanism for lionfish population control. In the Dry Tortugas, lionfish density in 2016 was significantly lower (0.6 ind ha−1 ± 0.15 SE) than the two other south Florida regions. The Dry Tortugas region has the highest percentage of marine protected areas, the lowest level of exploitation, and thus the highest densities of potential lionfish predators and competitors. In the Florida Keys and southeast Florida in 2016, lionfish densities were greater (5.4 ind ha−1 ± 1.0 SE and 9.0 ± 2.7 SE, respectively) than the Dry Tortugas. Fishing pressure on lionfish was higher in these two regions, but densities of several potential predators and competitors were substantially lower. Despite relatively low regional lionfish densities that can be attributed to some combination of fishing mortality and natural biocontrol, lionfish are still well established in the south Florida coral reef ecosystem, warranting continued concern

    Rapid Invasion of Indo-Pacific Lionfishes (\u3cem\u3ePterois Volitans\u3c/em\u3e and \u3cem\u3ePterois Miles\u3c/em\u3e) in the Florida Keys, USA: Evidence from Multiple Pre- and Post-Invasion Data Sets

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    Over the past decade, Indo-Pacific lionfishes, Pterois volitans (Linnaeus, 1758) and Pterois miles (Bennett, 1828), venomous members of the scorpionfish family (Scorpaenidae), have invaded and spread throughout much of the tropical and subtropical northwestern Atlantic Ocean and Caribbean Sea. These species are generalist predators of fishes and invertebrates with the potential to disrupt the ecology of the invaded range. Lionfishes have been present in low numbers along the east coast of Florida since the 1980s, but were not reported in the Florida Keys until 2009. We document the appearance and rapid spread of lionfishes in the Florida Keys using multiple long-term data sets that include both pre- and post-invasion sampling. Our results are the first to quantify the invasion of lionfishes in a new area using multiple independent, ongoing monitoring data sets, two of which have explicit estimates of sampling effort. Between 2009 and 2011, lionfish frequency of occurrence, abundance, and biomass increased rapidly, increasing three- to six-fold between 2010 and 2011 alone. In addition, individuals were detected on a variety of reef and non-reef habitats throughout the Florida Keys. Because lionfish occurrence, abundance, and impacts are expected to continue to increase throughout the region, monitoring programs like those used in this study will be essential to document ecosystem changes that may result from this invasion

    Ecological-economic assessment of the effects of freshwater flow in the Florida Everglades on recreational fisheries

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    This research develops an integrated methodology to determine the economic value to anglers of recreational fishery ecosystem services in Everglades National Park that could result from different water management scenarios. The study first used bio-hydrological models to link managed freshwater inflows to indicators of fishery productivity and ecosystem health, then link those models to anglers\u27 willingness-to-pay for various attributes of the recreational fishing experience and monthly fishing effort. This approach allowed us to estimate the foregone economic benefits of failing to meet monthly freshwater delivery targets. The study found that the managed freshwater delivery to the Park had declined substantially over the years and had fallen short of management targets. This shortage in the flow resulted in the decline of biological productivity of recreational fisheries in downstream coastal areas. This decline had in turn contributed to reductions in the overall economic value of recreational ecosystem services enjoyed by anglers. The study estimated the annual value of lost recreational services at 68.81million.Thelossesweregreaterinthemonthsofdryseasonwhenthewatershortagewashigherandthenumberofanglersfishingalsowashigherthanthelevelsinwetseason.Thestudyalsodevelopedconservativeestimatesofimplicitpriceofwaterforrecreation,whichrangedfrom68.81million. The losses were greater in the months of dry season when the water shortage was higher and the number of anglers fishing also was higher than the levels in wet season. The study also developed conservative estimates of implicit price of water for recreation, which ranged from 11.88 per AF in November to 112.11perAFinApril.Theannualaveragepricewas112.11 per AF in April. The annual average price was 41.54 per AF. Linking anglers\u27 recreational preference directly to a decision variable such as water delivery is a powerful and effective way to make management decision

    Assessing Coral Reef Fish Population and Community Changes in Response to Marine Reserves in the Dry Tortugas, Florida, USA

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    The efficacy of no-take marine reserves (NTMRs) to enhance and sustain regional coral reef fisheries was assessed in Dry Tortugas, Florida, through 9 annual fishery-independent research surveys spanning 2 years before and 10 years after NTMR implementation. A probabilistic sampling design produced precise estimates of population metrics of more than 250 exploited and non-target reef fishes. During the survey period more than 8100 research dives utilizing SCUBA Nitrox were optimally allocated using stratified random sampling. The survey domain covered 326 km2, comprised of eight reef habitats in four management areas that offered different levels of resource protection: the Tortugas North Ecological Reserve (a NTMR), Dry Tortugas National Park (recreational angling only), Dry Tortugas National Park Research Natural Area (a NTMR), and southern Tortugas Bank (open to all types of fishing). Surveys detected significant changes in population occupancy, density, and abundance within management zones for a suite of exploited and non-target species. Increases in size, adult abundance, and occupancy rates were detected for many principal exploited species in protected areas, which harbored a disproportionately greater number of adult spawning fishes. In contrast, density and occupancy rates for aquaria and non-target reef fishes fluctuated above and below baseline levels in each management zone. Observed decreases in density of exploited species below baseline levels only occurred at the Tortugas Bank area open to all fishing. Our findings indicate that these NTMRs, in conjunction with traditional fishery management control strategies, are helping to build sustainable fisheries while protecting the fundamental ecological dynamics of the Florida Keys coral-reef ecosystem

    Assessment of natural resource conditions in and adjacent to Dry Tortugas National Park

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    This project characterized and assessed the condition of coastal water resources in the Dry Tortugas National Park (DRTO) located in the Florida Keys. The goal of the assessment was to: (1) identify the state of knowledge of natural resources that exist within the DRTO, (2) summarize the state of knowledge about natural and anthropogenic stressors and threats that affected these resources, and (3) describe strategies being implemented by DRTO managers to meet their resource management goals. The park, located in the Straits of Florida 113 km (70 miles) west of Key West, is relatively small (269 square kilometers) with seven small islands and extensive shallow water coral reefs. Significant natural resources within DRTO include coastal and oceanic waters, coral reefs, reef fisheries, seagrass beds, and sea turtle and bird nesting habitats. This report focuses on marine natural resources identified by DRTO resource managers and researchers as being vitally important to the Tortugas region and the wider South Florida ecosystem. Selected marine resources included physical resources (geology, oceanography, and water quality) and biological resources (coral reef and hardbottom benthic assemblages, seagrass and algal communities, reef fishes and macro invertebrates, and wildlife [sea turtles and sea-birds]). In the past few decades, some of these resources have deteriorated because of natural and anthropogenic factors that are local and global in scale. To meet mandated goals (Chapter 1), resource managers need information on: (1) the types and condition of natural and cultural resources that occur within the park and (2) the stressors and threats that can affect those resources. This report synthesizes and summarizes information on: (1) the status of marine natural resources occurring at DRTO; and (2) types of stressors and threats currently affecting those resources at the DRTO. Based on published information, the assessment suggests that marine resources at DRTO and its surrounding region are affected by several stressors, many of which act synergistically. Of the nine resource components assessed, one resource category – water quality – received an ecological condition ranking of "Good"; two components – the nonliving portion of coral reef and hardbottom and reef fishes – received a rating of "Caution"; and two components – the biotic components of coral reef and hardbottom substrates and sea turtles – received a rating of "Significant concern" (Table E-1). Seagrass and algal communities and seabirds were unrated for ecological condition because the available information was inadequate. The stressor category of tropical storms was the dominant and most prevalent stressor in the Tortugas region; it affected all of the resource components assessed in this report. Commercial and recreational fishing were also dominant stressors and affected 78% of the resource components assessed. The most stressed resource was the biotic component of coral reef and hardbottom resources, which was affected by 76% of the stressors. Water quality was the least affected; it was negatively affected by 12% of stressors. The systematic assessment of marine natural resources and stressors in the Tortugas region pointed to several gaps in the information. For example, of the nine marine resource components reviewed in this report, the living component of coral reefs and hardbottom resources had the best rated information with 25% of stressor categories rated "Good" for information richness. In contrast, the there was a paucity of information for seagrass and algal communities and sea birds resource components
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