TY - JOUR
T1 - The importance of physical and biogenic structure to juvenile fishes on the shallow inner continental shelf
AU - Diaz, R. J.
AU - Cutter, G. R.
AU - Able, K. W.
N1 - Funding Information: We present part of a larger study funded by Minerals Management Service to evaluate existing living resources and the potential for impacts on those resources associated with mining of sand for beach nourishment from the shallow inner-continental shelf (Cutter and Diaz 2000). We would like to thank the crews of the M/V Atlantic Surveyor from Toms River, New Jersey (1998 cruise) and the University-National Oceanographic Laboratory System vessel R/V Cape Henlopen of the University of Delaware (1999 cruise). Stacy Hagan and Roger Hoden assisted with sampling at sea. This study was supported by the Department of the Interior, Minerals Management Service under the guidance of Barry Drucker (Contract No. 1435-01-97-CT-30853). New Jersey Sea Grant provided additional support for analysis of data. This paper is Virginia Institute of Marine Science contribution number 2513 and contribution number 2003-01 of the Rutgers University Institute of Marine and Coastal Sciences.
PY - 2003/2
Y1 - 2003/2
N2 - Fish-habitat relationships on the shallow inner continental shelf were quantified with video sled and metered beam trawl on Fenwick and Weaver shoals offshore of Maryland and Delaware, U.S. These areas provide megascale physical relief and habitat complexity, but for juvenile fishes, mesoscale and microscale habitat is very important particularly as refuge from predation. At these smaller scales, much of the relief on the inner continental shelf is contributed by bedforms or sand waves and biogenic structures such as tubes, shell beds, or pits. A quantitative association for juvenile fishes between and within benthic habitats was found and related primarily to bedform size and amount of biogenic structure. The incidence of fishes was about four-times higher for large bedforms (> 30 cm wavelength and about 10 cm crest height) relative to smaller bedforms (< 30 cm wavelength and about 5 cm crest height). For biogenic structure, going from high patch-mat tube densities to lower densities or no biogenic structure increased fish incidence by 5.4 and 3.3 times, respectively. The significant relationships of fishes with bedform size and density of biogenic structure indicated that seemingly small differences in physical structure of a habitat can make the difference between unacceptable and essential habitat for juvenile fishes. Proximity of complex and simple habitats was important in the diel use of habitat and in balancing pressure of refuge from predation provided by complex habitats with foraging for increased resources available in simpler habitats. During the day, spatially complex habitats comprised of Diopatra and Asabellides tube mats had about twice as many fishes relative to bare sandy habitats (8.3-9.9 versus 4.0-4.1 fishes 100 m-2, respectively). At night, the pattern was reversed with more fishes present in the bare sandy habitats (12.4-13.5 versus 5.6-8.7 fishes 100 m-2). Some fish, such as Ammodytes spp., were very habitat specific and occurred only on dynamic coarser sands near the top of the shoals. Others, such as Urophycis regia, showed less habitat preference and occurred in all habitats during both day and night. Combining the effects of physical relief and biogenics, the habitat with the highest incidence of fishes had large bedforms with some biogenic structure. More emphasis needs to be placed on quantifying the relationship between fishes and their habitats for the fisheries management concept of essential fish habitat to develop into an effective tool on the inner continental shelf. The juvenile life history stages need to be emphasized because fish-habitat interactions are the strongest for these stages and may be the most ecologically important.
AB - Fish-habitat relationships on the shallow inner continental shelf were quantified with video sled and metered beam trawl on Fenwick and Weaver shoals offshore of Maryland and Delaware, U.S. These areas provide megascale physical relief and habitat complexity, but for juvenile fishes, mesoscale and microscale habitat is very important particularly as refuge from predation. At these smaller scales, much of the relief on the inner continental shelf is contributed by bedforms or sand waves and biogenic structures such as tubes, shell beds, or pits. A quantitative association for juvenile fishes between and within benthic habitats was found and related primarily to bedform size and amount of biogenic structure. The incidence of fishes was about four-times higher for large bedforms (> 30 cm wavelength and about 10 cm crest height) relative to smaller bedforms (< 30 cm wavelength and about 5 cm crest height). For biogenic structure, going from high patch-mat tube densities to lower densities or no biogenic structure increased fish incidence by 5.4 and 3.3 times, respectively. The significant relationships of fishes with bedform size and density of biogenic structure indicated that seemingly small differences in physical structure of a habitat can make the difference between unacceptable and essential habitat for juvenile fishes. Proximity of complex and simple habitats was important in the diel use of habitat and in balancing pressure of refuge from predation provided by complex habitats with foraging for increased resources available in simpler habitats. During the day, spatially complex habitats comprised of Diopatra and Asabellides tube mats had about twice as many fishes relative to bare sandy habitats (8.3-9.9 versus 4.0-4.1 fishes 100 m-2, respectively). At night, the pattern was reversed with more fishes present in the bare sandy habitats (12.4-13.5 versus 5.6-8.7 fishes 100 m-2). Some fish, such as Ammodytes spp., were very habitat specific and occurred only on dynamic coarser sands near the top of the shoals. Others, such as Urophycis regia, showed less habitat preference and occurred in all habitats during both day and night. Combining the effects of physical relief and biogenics, the habitat with the highest incidence of fishes had large bedforms with some biogenic structure. More emphasis needs to be placed on quantifying the relationship between fishes and their habitats for the fisheries management concept of essential fish habitat to develop into an effective tool on the inner continental shelf. The juvenile life history stages need to be emphasized because fish-habitat interactions are the strongest for these stages and may be the most ecologically important.
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U2 - https://doi.org/10.1007/BF02691689
DO - https://doi.org/10.1007/BF02691689
M3 - Article
SN - 0160-8347
VL - 26
SP - 12
EP - 20
JO - Estuaries
JF - Estuaries
IS - 1
ER -