Fisheries Research Articles
Implications of the divergent use of a suite of estuaries by two exploited marine fish species
Document Type
Article
Publication Date
9-1-2011
Journal Title
Journal of Fish Biology
ISSN
Print: 0022-1112 Electronic: 1095-8649
Keywords
Age Distribution; Animals; Body Weight; Ecosystem; Female; Fisheries; Gonads / growth & development; Male; Oocytes / physiology; Perciformes / growth & development;
Disciplines
Aquaculture and Fisheries | Marine Biology
Abstract
Biological characteristics of the marine species King George whiting Sillaginodes punctatus and Australian herring Arripis georgianus in three seasonally open estuaries (Broke, Irwin and Wilson Inlets), one permanently open estuary (Oyster Harbour) and one normally closed estuary (Wellstead Estuary) on the south coast of Western Australia have been determined and compared. Sillaginodes punctatus enters the seasonally and permanently open estuaries early in life and reaches total lengths (L(T)) >280 mm at which it can be legally retained and thus contributes to commercial and recreational fisheries in these systems. This sillaginid almost invariably emigrates from these estuaries before reaching its typical size at maturity (L(T50)) and does not return after spawning in marine waters. In contrast, virtually all female A. georgianus (≥ 98%) in the three seasonally open estuaries and the majority in the normally closed (89·5%) and permanently open estuaries (83%) exceeded the L(T50) of this species at maturity, reflecting the fact that the nursery areas of this species are predominantly located much further to the east. Although adult females of A. georgianus in seasonally open and normally closed estuaries had developed mature ovaries by autumn, at which time they were prevented from migrating to the sea by closure of the estuary mouths, this species did not spawn in those estuaries. The oocytes in their ovaries were undergoing extensive atresia, a process that had been incipient prior to oocyte maturation. As the adult females of A. georgianus in the permanently open Oyster Harbour at this time all possessed resting gonads, i.e. their oocytes were all previtellogenic, the adults that were present in that estuary earlier and were destined to spawn in autumn must have emigrated from that permanently open estuary to their marine spawning areas prior to the onset of gonadal recrudescence. The body masses at length of A. georgianus, which were almost invariably higher in summer and autumn than in winter and spring, were greater in the very productive environments of the seasonally open and normally closed estuaries than in the less productive and essentially marine environment of Oyster Harbour and coastal marine waters. In general, the same pattern of differences between water bodies was exhibited by the growth of A. georgianus and by the more restricted data for body mass at L(T) and growth of S. punctatus. Despite an increase in anthropogenic activities in Wilson Inlet over the last two decades, the growth of both species was very similar to that recorded 20 years earlier. The fisheries implications of the results for the two species are discussed.
Recommended Citation
Potter, I C,
Chuwen, B M,
Hesp, S A,
Hall, N G,
Hoeksema, S D,
Fairclough, D V,
and
Rodwell, T M.
(2011), Implications of the divergent use of a suite of estuaries by two exploited marine fish species. Journal of Fish Biology, 79 (3), 662-691.
https://library.dpird.wa.gov.au/fr_fja/185
