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Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause

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Bivalve coral reefs increase the production of finfish and macrocrustaceans

Oysters and mussels are thought to produce dense beds or coral reefs worldwide that can develop to several meters deep. As such, they are estuarine and high-latitude analogues of coral reefs, often consisting of a large number of calcium carbonate structures with the outer layer of living bivalves. Bivalve habitats also support a generally diverse and dense concentration of associated organisms. Although there is strong anecdotal evidence that mussel habitat is important for fish production, there are currently no quantitative measures for this impact.

Mussel bed habitats are being restored on an experimental scale in Port Phillip Bay in Australia and Haruki Bay in New Zealand, as well as in the Penn shell, with the aim of improving water quality and producing fish, particularly pink snapper, a popular recreational species. Similarly, the El Manglito fishing community near La Paz, Mexico, has traditionally made a living fishing in Ensenada and La Paz Bay.

Quantify the history of fish production in oyster habitats, which have long been harvested by coastal communities. Since the first century AD, the Romans imported oysters from as far away as the south of England. The rise of mechanized fishing has led to the collapse of global oyster populations. As a result, oyster restoration efforts have long been part of wild oyster fisheries in many parts of the world.

However, it is only recently that work in the United States has paved the way for the restoration of oyster habitats, providing a variety of services provided by this habitat in addition to oyster fisheries. This is a conservation action that has received a high level of support as the ecosystem service benefits provided by oyster habitats are better understood.

Another motivation for quantifying fish production in marine habitats is the concept of basic fish habitat, which was introduced into fisheries management in many jurisdictions from the mid-1980s and 1996 through the Magnuson-Stephenson Fisheries Conservation and Management Act. By linking fish production to habitats, the Act seeks to broaden the focus of fisheries management to include consideration of the ecosystem's ability to produce fish, rather than focusing solely on limiting extraction from target species stocks.

Changes in habitat dependence in different age groups of many fish and macrocrustaceans complicate the measurement of relative values of fish production for these species by habitat. A comprehensive accounting of fish production requires an assessment of habitat contributions to fish production by fish of all age classes.

Quantification of increased fish production in oyster habitats, quantitative data on the extent to which fish and macroinvertebrates are enhanced by bivalve habitats are rare outside the United States. While recent progress has been made in understanding the role of Modiolus modiolus in Europe as an important habitat for the commercially important conch Buccinum undatum, for most bivalve habitats outside the United States, evidence is limited to historical documentation on species numbers.

In order to quantify the increase in fish and invertebrate production from bivalve habitats, it is necessary to measure the abundance of target age classes within habitats relative to places without habitats. Therefore, repeat and paired density data from contrast habitats are essential to support this quantification.

By collating available data on paired oyster reef fish and invertebrates from 31 studies in the United States, zu Ermgassen et al. identified species where juvenile fish were consistently more abundant in oyster habitat than unstructured sediment habitat. These habitats often replace oyster reefs when they disappear and are therefore considered the most suitable control habitats for comparison. They also found significant differences in biogeographic regions in oyster reef-enhanced fish and invertebrate species, with 12 species in the Mid-Atlantic and South Atlantic and 19 juvenile species in the Gulf of Mexico.

By applying established growth and mortality estimates to the increased density of juvenile fish found on oyster reefs, zu Ermgassen et al. estimated year-on-year yields for each species that continued to strengthen. This indicates an increase in the presence of oyster reef habitats compared to unstructured benthic habitats.

In this case, the production value increases over time as the oyster habitat grows for successive generations and years. The error distribution is also calibrated for variance obtained from the original publication. Many of these species enhanced as juvenile fish have direct fishery value, others represent prey for forage fish and highly nutrient fishery species, and in this approach, only the contribution of species that directly benefit from oyster reefs as juvenile nurseries can be fully quantified.

Given the global distribution of bivalve habitats, estimates of fish production in oyster habitats are well documented and available, even for a small area, and provide the ability to influence fisheries management in two important ways. It provides logic that fundamentally changes the paradigm of fisheries management, based on consideration of multiple stakeholder groups affected by changes in service levels provided by bivalve habitats, as well as harvesting. It also introduces the option to include bivalve habitats in the management considerations of finfish and macrocrustacean species supported by these habitats, in a true ecosystem-based fisheries management (EBFM) scenario.

Bibliography:

[1] Alleway HK, Connell SD (2015) Losing an ecological baseline by eradicating oyster reefs from coastal ecosystems and human memory. Conservation Biol 29(3): 795–804. Web link

[2] Baker MW, Oyster Reef Risks and Recommendations for Conservation, Restoration and Management. Biosci 61(2): 107–116

[3] Berkes E (2012) Implementing ecosystem-based management: evolution or revolution? Fish 13: 465-476

[4] Blandon A, zu Ermgassen PSE (2014) Quantitative estimation of commercial fish enhancement in seagrass habitats in southern Australia. Estuarine Coastal Shelf Sci 141: 1-8

Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause
Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause
Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause
Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause
Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause
Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause
Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause
Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause
Bivalve reefs increase the production of finfish and macrocrustaceans Oysters and mussels are thought to produce dense beds or reefs worldwide, which can develop to several meters deep. cause

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