Spatial and temporal patterns of habitat use by three estuarine species of mysid shrimp

Abstract

Abstract. The mysids Rhopalopthalmus egregius, Haplostylus dakini and Doxomysis australiensisare abundant yet unstudied omnivorous crustaceans in Australian estuaries. Habitat use and population dynamics were investigated for these species over spring and summer in the Tweed River, Australia, to explore their ecological role in estuarine ecosystems. Overall, mysids were concentrated in shallow unvegetated and deep unvegetated estuarine habitats. H. dakini were most abundant in shallow and deep bare habitats at night, whereas R. egregius were most abundant in deep bare habitats during the night. D. australiensis were present across all habitats in the night, but negligible numbers were present during the day. Significantly greater numbers of R. egregius and D. australiensis were sampled during the new moon, compared with the full moon. Significantly larger R. egregius and D. australiensis individuals were present in benthic habitats at night, indicating possible partitioning of habitat for juvenile and adult subpopulations. Adaptive foraging strategies and habitat use facilitates the coexistence of sympatric mysid species, H. dakini and R. egregius, and within-species habitat partitioning allowed juvenile R. egregius to avoid interaction with adult R. egregius. The observed dynamics minimize interand intra-specific predation between mysids, and by other predators, while optimizing access to key trophic resources.

Life history and reproduction of two abundant mysids (Mysidacea: Mysidae) in an intermittently open New Zealand estuary

“…This pattern of distribution and abundance is consistent with other New Zealand studies (Chapman and Lewis 1976;Jones et al 1989) and may be related to salinity preferences, with T. chiltoni preferring brackish to freshwater conditions and T. novae-zealandiae preferring higher salinities (Jones et al 1989). Such segregation may also reduce inter-specific competition and predation (Taylor 2008).…”

“…Like most temperate littoral and estuarine mysids, densities of T. chiltoni and T. novae-zealandiae exhibited seasonal peaks in abundance related to major breeding events from spring to autumn, with a decline in abundance over winter. Similar seasonal dynamics have been shown for mysid species in South Africa (Wooldridge 1981) and Australia (Taylor 2008).…”

Age-specific light preferences and vertical migration patterns of a Great Lakes invasive invertebrate, Hemimysis anomala

“…If juvenile Hemimysis are less sensitive to higher light levels than adults (as is the case with other littoral mysid shrimp species-e.g., Kouassi et al, 2006;Taylor, 2008), we would expect: (1) to see emergence of juveniles from the benthos into the water column at an earlier hour than adults, and (2) the relative proportion of juvenile Hemimysis: adult Hemimysis in the water column to decrease with decreasing light levels. Similarly, if there are no significant differences in light preferences between size groups then we would expect emergence behaviors to be the same regardless of light level and that the adult: juvenile ratio in the water column would not vary with light level.…”

Post‐release monitoring of site and group fidelity in acoustically tagged stocked fish

“…Juvenile A. japonicus predominately feed on mysid shrimp (Taylor et al . ), which are abundant within New South Wales estuaries (Taylor ), and inhabit deep areas within estuaries (Taylor et al . ).…”