Fish Habitat: Essential Fish Habitat and Rehabilitation

<em>Abstract</em> .—Basic research on the settlement and postsettlement ecology of spiny lobster <em>Panulirus argus </em> has led to an application with the potential to replace lost natural refuge with artificial shelters intended for the vulnerable small juvenile stages. We began investigating ecological processes regulating juvenile spiny lobster recruitment in the Florida nursery in the mid-1980s. An unprecedented massive die-off of sponges in the middle Florida Keys followed cyanobacterial blooms in 1991–1993, ultimately affecting about 300 km2 of a region providing approximately one-fifth of total juvenile recruitment. Before 1991, crevices in sponges provided diurnal refuge from predators for about 70% of juveniles <50 mm carapace length. On the basis of sampling done before and after sponge loss, we estimated that juvenile abundance declined by 30–50% on spongeless sites without alternative shelter, resulting in a decrease of annual nurserywide potential of up to 10%. Results of a field experiment evaluating the relative influences of the magnitude of settlement and availability of crevice shelter on juvenile recruitment, fortuitously begun before the sponge die-off, showed that juvenile survival and abundance were sustained on small 0.02- to 0.07-ha test sites provided with supplemental artificial shelters (slotted concrete blocks). In the absence of sponges, survival of microwire-tagged juveniles on the shelter-supplemented sites was about six times higher than that on unsupplemented sites. On the basis of our earlier ecological findings, we devised a feasibility study to test whether the artificial shelters could replace lost sponge shelter for juvenile lobsters on a large scale. It took the form of a field experiment using 240 shelters spread over 1-ha sites located amid hard substrate denuded of sponges. The shelters provided substitute crevices, supporting juvenile lobster recruitment approximating that in areas with good sponge cover. This outcome exemplifies the essential value of initial basic research that provides understanding of the ecological processes regulating individual survival and, ultimately, the character and dynamics of the fishery population. Such an approach, and the information it provides, is necessary to successful rehabilitation of essential habitat or restocking of natural populations. Moreover, conducting basic research can help prevent the waste of precious time, funds, income, and human effort that typically has occurred in past failed attempts that were undertaken with insufficient knowledge. We urge the fisheries-ecology discipline and support agencies to promote strongly the primacy of research on basic processes.

Fish Habitat: Essential Fish Habitat and Rehabilitation

<em>Abstract.—</em> The quality and quantity of habitats determine ecosystem productivity. Hence, they determine the potential fish productivity that sustains the fish harvests extractable from freshwaters and seas. Efforts to conserve and protect fish habitats are frustrated by key unanswered questions: which habitat types and how much must be protected to ensure natural self-sustaining fish stocks? Minns and Bakelaar presented a prototype method for assessing suitable habitat supply for fish stocks in Lake Erie, an analysis that can be used to address conservation issues. Here, the method is refined and extended, taking the assessment of habitat supply for pike <em>Esox lucius </em> in the Long Point region of Lake Erie as a case study. As with the previous study, much emphasis is placed on “learning by doing.” Because available inventories of habitat features are coarse and incomplete, improved guidelines for estimating habitat supply are expected from these prototype studies. The habitat supply method previously presented by Minns and Bakelaar is elaborated in three ways here: (1) the basic physical habitat assessment is derived from a remote-sensing inventory database; (2) methods of quantifying the thermal regime and integrating it with other habitat elements are examined; (3) habitat supply estimates are used in a pike population model, and pike biomass and production are simulated for the Long Point region of Lake Erie and then compared with available records. The roles of error and uncertainty are examined for all elements in the estimation and application of suitable habitat supply values. There is potential for supply measurement and analysis to guide fish habitat management.

Fish Habitat: Essential Fish Habitat and Rehabilitation

<em>Abstract.—</em> Ohio constructed two artificial reefs beginning in 1986 in Lorain and Cuyahoga counties. The reefs were a demonstration project to evaluate the effects of reefs on fishing satisfaction and the feasibility of reef construction in other areas. Evaluation of the effects of reefs on recreational activity was viewed as essential for further reef development in Ohio and other Great Lakes states. A two-pronged research effort was undertaken: an underwater video investigation and a travel cost study. The travel cost study estimated the economic value derived from use of the Lorain County reef by sport anglers and divers. The results of this research were critical in supporting construction of a large artificial reef off the coast in Cleveland (Cuyahoga County) using rubble from the old Cleveland Stadium. From April to October 1992, 850 individuals who were willing to participate were contacted at Lorain County marinas and launch ramps. In early February 1993, these individuals were mailed questionnaires, with a second questionnaire mailed to nonrespondents in late February. Fifty-five percent responded. We estimated three alternative single-equation travel cost models. The most conservative estimate of consumer surplus (economic value) showed that the typical angler who used the reef in 1991 made nearly 10 more fishing trips during 1992 than the typical angler who did not use the reef in 1991, that is, nearly 26 trips in 1992 compared to 16 trips in 1992 by those who did not use the reef in 1991. The most conservative estimate of consumer surplus also showed that anglers who used the reef before 1992 valued total angling activity at US$302 more for the year 1992 than anglers who did not use the reef before 1992. When aggregated across all Lorain County anglers using the reef during 1991, the total value of the reef was $276,000 in 1992 compared to total construction costs of less than $100,000. Thus, the consumer surplus generated by the reef in one year exceeded construction costs by a wide margin.

Fish Habitat: Essential Fish Habitat and Rehabilitation

<em>Abstract.</em> —The Coquille watershed contains the largest coastal river originating within the Coast Range of Oregon. The Coquille River presently supports over 57 species of fish including coho salmon <em>Oncorhynchus kisutch</em> , spring and fall chinook salmon <em>O. tshawytscha</em> , resident and sea-run cutthroat trout <em>O. clarki</em> , winter steelhead trout <em>O. mykiss</em> , and a remnant population of chum salmon <em>O. keta</em> . Coho salmon have been listed as threatened under the Endangered Species Act. Many factors including habitat alterations, harvests, hatchery introductions, and ocean conditions have led to the decline of many Coquille River fish stocks. Habitat changes since European settlement began in the mid- 1800s include logging and log transport, road building, draining and diking for agriculture, and urbanization, which have all contributed to the decline of fish stocks and water quality within the watershed. The recognition of habitat problems as a key limiting factor for fish production and water quality led to the formation of the Coquille Watershed Association (CWA) in early 1994. The formation of the CWA was another step in a 20-year local effort to address habitat problems through restoration of natural processes. The CWA is organized as a nonprofit corporation and is governed by a 26-member executive council representing landowners and stakeholders within the watershed. The goals of the CWA, which arrives at decisions through consensus, include creating water quality conditions that will meet Clean Water Act standards and enhancing native fish survival and production through public and private partnerships. To reach those goals, the CWA has organized a technical advisory group and developed an Action Plan that address limiting factors and sets priorities for identifying, prioritizing, coordinating, accomplishing, and monitoring restoration projects and educational efforts. To date the CWA has generated over US$2.5 million in public and private funding to implement projects including riparian restoration through fencing and planting, wetland development, the addition of large-channel wood and rock, off-channel livestock watering, and over 40 educational tours.

Fish Habitat: Essential Fish Habitat and Rehabilitation

<em>Abstract.—</em> A need exists to scientifically determine optimal fish habitats to support decision making for management of essential fish habitat. Scientists have been collaborating to conduct habitat suitability index (HSI) modeling to spatially delineate fish habitats for estuarine fish and invertebrate species in Tampa Bay and Charlotte Harbor, Florida. Results from HSI modeling of juvenile spotted seatrout <em>Cynoscion nebulosus </em> in Charlotte Harbor are presented. Data obtained from 1989–1997 by fisheries-independent monitoring in the two estuaries were used along with environmental data from other sources. Standardized catch-per-unit-effort (catch rates) were calculated across gear types using fisheries-monitoring data from Charlotte Harbor and Tampa Bay. Suitability index functions were determined using three methods: (1) frequency of occurrence, (2) mean catch rates within ranges, and (3) smooth-mean catch rates determined by polynomial regression. Mean catch rates were estimated within biologically relevant ranges and, where sufficient data were available, for finer intervals across environmental gradients. Suitability index functions across environmental gradients were then derived by scaling catch rates. Gridded habitat layers for temperature, salinity, depth, and bottom type in Charlotte Harbor were also created using a geographic information system. Habitat suitability index modeling was conducted using the U.S. Fish and Wildlife Service geometric mean method linked to the ArcView Spatial Analyst module. The model integrated suitability indices associated with the habitat layers for Charlotte Harbor to create a map of the predicted distribution for juvenile spotted seatrout during the fall season. Suitability indices developed for Tampa Bay were used with Charlotte Harbor habitat layers to test transfer of the indices to another estuary. Predicted HSI maps depicted low to optimum habitat suitability zones in Charlotte Harbor. Model performance was evaluated by statistically comparing the relative ranking of mean catch rates with mean suitability indices for corresponding zones. Suitability indices obtained using polynomial regression methods yielded morereliable HSI maps for juvenile spotted seatrout than those derived using mean catch rates within biologically relevant ranges. The observed map, derived using smooth-mean suitability indices transferred from Tampa Bay, was not significantly different (Chi-square goodness-of-fit test) from the expected map derived using smooth-mean indices from Charlotte Harbor. Our modeling efforts using transferred indices indicate that it is possible to predict the geographic distributions of fish species by life stage in estuaries lacking fisheries monitoring.

Fish Habitat: Essential Fish Habitat and Rehabilitation

<em>Abstract</em> — The increasing concern about impacts of bottom trawling, scallop dredging, and other mobile fishing methods has focused primarily on effects on commercial fisheries, but these fishing activities also act more broadly on benthic biological diversity. Because the seabed is erroneously envisioned as a featureless, nearly lifeless plain, impacts of commercial fishing gear have long been underestimated. Structures on and in the seabed, including biogenic structures (reef corals, kelp holdfasts, shells, tubes, and tunnels), create a diversity of habitat patches. They provide refuges from predation and feeding places for demersal fishes and other species. Benthic structural complexity is positively correlated with species diversity and postsettlement survivorship of some commercial fishes. Mobile fishing gear disturbs the seabed, damaging benthic structures and harming structure-associated species, including commercially important fishes, although some other commercial fish species can persist where seabed structures have been removed. Bottom trawling is therefore similar to forest clear-cutting, but it is far more extensive and is converting very large areas of formerly structurally complex, biologically diverse seabed into the marine equivalent of low-diversity cattle pasture. In contrast with the U.S. National Forest Management Act, which governs use of living resources in federally owned forestlands, the 1996 Magnuson-Stevens Fishery Conservation and Management Act does not prevent ecosystem “type conversion” and ignores the need to maintain biological diversity. Preventing further loss of marine biodiversity and key fisheries will depend on our willingness to protect marine areas from effects of mobile fishing methods.

Fish Habitat: Essential Fish Habitat and Rehabilitation

<em>Abstract</em> .—Food production in the United States from ocean fisheries is leveling off after impressive growth in the 1970s and 1980s. Fishery officials project further gains through more effective regulation of harvests and reduced discarding of catch. In the longer term, however, the most important opportunity to boost production involves rehabilitating fishery habitats that have been damaged or lost because of poor management. Many thousand tons of additional seafood production can be “unlocked” for fishermen and consumers if habitats are restored. Changes in 1996 to the Magnuson- Stevens Fishery Conservation and Management Act (the Magnuson-Stevens Act) call for the mapping of these habitats and the inclusion of habitat concerns in fishery management planning. These new requirements, if properly implemented, will help focus the attention of fishermen and seafood consumers on what is being lost and what needs to be done to restore productivity. Although these requirements are a good first step, the rules and guidance for the new essential fish habitat (EFH) provisions are fundamentally flawed. For example, the rules to implement EFH provisions muddle the Magnuson-Stevens Act’s definition of EFH with numerous references to prey species and vague ecological ideas. Especially troubling is the introduction by the National Marine Fisheries Service through the rules of the concept of “contribution to a healthy ecosystem” as an apparent standard for delineating necessary amounts of EFH. In addition, it is important to remember that competition among fishing fleets is fierce, and the promise of these new habitat requirements could be lost if habitat concerns become enmeshed in the ongoing political battles for harvest allocations.

Fish Habitat: Essential Fish Habitat and Rehabilitation

<em>Abstract.</em> —The Canada-U.S. Great Lakes Water Quality Agreement (GLWQA) is an evolving instrument for ecosystem-based management. Its initial emphasis in 1972 was on controlling phosphorus inputs. In 1978, the GLWQA focused on control and management of persistent toxic substances and the use of an ecosystem approach in management and research. The 1987 Protocol to the GLWQA adopted new annexes mat focused on sources and pathways of persistent toxic substances and on development and implementation of comprehensive management plans to restore beneficial uses, including fish and wildlife habitat. Canada and the United States have achieved a number of Great Lakes successes. Examples of successes include: reversing cultural eutrophication in the lower Great Lakes and maintaining the oligotrophic-mesotrophic state of the upper Great Lakes as a result of phosphorus control programs, and achieving US$2-4 billion in economic return to the Great Lakes region annually as a result of fish stocking, restrictions on harvests, and sea lamprey control. As such successes have been achieved and cooperative management efforts have evolved to address ecosystem integrity and sustainability, the relative importance of habitat as a Great Lakes issue has increased. Current major challenges to further ecosystem-based management of habitat include: ensuring that all levels of government adopt strong habitat conservation and rehabilitation policy statements; recruiting and retaining trained habitat personnel to ensure that local and regional actions are consistent with such policies; sustaining creative ecosystem-based processes in light of government cutbacks; addressing the need for fish habitat assessment and analysis via effective institutional arrangements; agreeing on a core set of indicators and allocating required resources to sustain monitoring programs; and exchanging information about successful experiences with modifying habitat to support fish stocks and communicating broadly both ecological and economic benefits.