Ko. Coyle et Rc. Highsmith, BENTHIC AMPHIPOD COMMUNITY IN THE NORTHERN BERING SEA - ANALYSIS OF POTENTIAL STRUCTURING MECHANISMS, Marine ecology. Progress series, 107(3), 1994, pp. 233-244
The age class structure of ampeliscid populations is determined largel
y by competition for space. Population densities of the various ampeli
scid species are regulated by a balance between required carbon flux r
ates to the seafloor, predation rates, competition for space and repro
ductive potential. The largest taxa require high organic matter input
and low predation rates to mature and reproduce. Reductions in organic
matter flux favor smaller taxa. Low predation rates favor larger taxa
, which can out-compete the smaller taxa for available space. High pre
dation rates favor smaller taxa, which have a higher reproductive rate
and are therefore more effective colonizers. The above factors can ex
plain the relative concentrations of Ampelisca macrocephala, Ampelisca
birulai and Byblis spp., the most abundant ampeliscids in the norther
n Bering Sea. Elevated predation losses to gray whales will depress th
e density of the large-sized A. macrocephala populations and increase
the density of the smallest species, A. birulai. Global warming should
elevate ampeliscid food requirements, and may also lead to elevated p
redation rates, both selecting for smaller species.