Comparisons of fauna among natural and transplanted eelgrass Zostera marIna meadows: criteria for mitigation

Numencal abundance, species composition and size of fish and shrimp were compared among (1) unvegetated, (2) transplanted (3) recently seed-colonized and (4) matule, natural eelgrass habitats to determine the equivalence of transplanted eelgrass beds to their natural counterparts In general, fish and shrimp were most abundant in mature natulal eelgrass habitats and least abundant in unvegetated habitats We developed a vector-graphical analysls that shows eplbenthic faunal abundance to be closely coupled with eelgrass bed development In an area where transplants performed poorly, the faunal component had a different composition and significantly lower numerical abundance In companson to natural beds Fauna1 abundance and composition in a 1 9-yr-old transplanted bed and a 6-mo-old seed-developed bed were indistinguishable from mature natural eelgrass beds Our data Indicate that recruitment of fish and shrimp to eelglass habitats established through transplantahon can occur in time, though not as rapidly as with naturally-seeded beds Area1 shoot density may serve as an inexpensive diagnostic parameter of functional equivalence for most resident macroeplfauna Abundance data need to be interpreted through functional mechanisms such as predation which act to produce the observed abundances in older to separate habitat function from dysfunchon Restored seagrass habitats have the potential to make substantial contributions to fish and shrimp production provided the habitats persist