Ecology of the Arrow Squid (Nototodarus gouldi) in Southeastern Australian Waters: A Multi-Scale Investigation of Spatial and Temporal Variability.

摘要: Phenotypic plasticity together with a short lifespan, rapid growth and the ability to move over considerable distances mean that squid populations are extremely responsive changing environmental conditions, this generates highly variable complex patterns of population ecology. This study examined population ecology ommastrephid Nototodarus gouldi in southern Australian waters; investigating how distribution abundance vary space time, factors may be driving these patterns. Broad scale GIS statistical (GAM GLM) analyses trawl fishery observer data identified clear ‘hotspots’ N. southeastern waters, which corresponded areas significant mesoscale oceanographic activity (i.e. strong shelf break fronts, convergence zones upwelling). Abundance was seasonal, but seasonality varied between locations. Remotely sensed sea surface temperature chlorophyll-a concentration were unable account for spatio-temporal encounter catch rates, possibly due temporal mismatch local evidence its effect on gouldi. Lagged relationships conditions then an annual one region- Bonney Coast, a ‘hotspot’ area subject seasonal upwelling activity. Local wind speed ENSO both strongly correlated abundance, most likely their influence mixing activity, thus prey availability. Cross validation linear model incorporating variables suggested reasonably good predictive ability. A negative correlation jig derived indices however suggests inter-annual variability is driven by distributional changes as well recruitment variability, depth response position front. Population structure life history characteristics inshore ground Tasmania exhibited four years, although not always consistent two sexes, particularly relative levels reproductive investment. also over this year period there no relationship biological available abundance. Squid high similar size age those sampled years low abundance; change biomass therefore attributed numbers squid. Nototodarus appear undertake ontogenetic bathymetric migrations, recruiting small juveniles, growing maturing the summer before moving away, into deeper waters where large mature individuals caught trawlers. sex ratio season indicates males leave grounds earlier than females. Tracking using automated acoustic telemetry array showed moved away from grounds, movement any way synchronous, individualseason tracking study- very In contrast, persistence when increased longer residency times accumulation individuals. Thus, ecology gouldi, like many other commercially exploited squid, appears closely linked hydrography ocean productivity. They greatest strongly defined or present (e.g. upwelling), cycles related and nature oceanography. Further investigations needed elucidate finer-scale detail mechanisms these patterns. particular, investigation linkages ontogeny distribution appear critical understanding development appropriate assessment models.s apparently leaving extended time study-a the persistence exploited ommastrephid ocean productivity. upwelling), and to elucidate and trawl for the models.