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Abstract Determining the hazards posed by microplastics (MPs,

Foundation species are being restored into inherently variable landscapes with multiple, interspersed habitats. However, understanding of the influence of different neighbouring habitats on community assembly and the survival of restored species is limited, despite their significant potential to affect restoration outcomes. We tested how habitat‐setting (being next to seagrass, seagrass and mangroves, or unvegetated sediments) and predation (by meso‐ and/or large predators) influenced macroinvertebrate community assembly and the survival of juvenile Sydney rock oysters (Saccostrea glomerata) on experimental oyster reef units in the Port Hacking estuary, New South Wales, Australia. Each habitat‐setting produced a distinct macroinvertebrate community on experimental reefs, whereas predation had limited effects on community structure. Juvenile oysters were instead highly predated everywhere, and oyster predation was dominated by the large, transient fish Acanthropagrus australis. Our findings allow practitioners to predict and tailor the communities which establish on restored oyster reefs by strategically placing them next to different habitats. If sites have a high predation risk but require seeding for reefs to establish, then caging or complex substrates must be used to increase seeded oyster survival. [ABSTRACT FROM AUTHOR]

The reproductive cycle of the tropical black-lip rock oyster Saccostrea echinata was determined at three locations in the Northern Territory, Australia. Wild oysters were collected every 4-6 wk (n = 13-23) from January 2016 until June 2017. Biometric and condition index data were collected, and tissues were histologically examined to determine gonad index (GI) and gender ratios. Seawater and air temperature were monitored by intertidally deployed data loggers, and daily rainfall data were obtained from local weather stations. A total of 527 oysters were sampled across all sites, of which 34.2% were females, 47.4% were males, 0.4% were hermaphrodites, and 18.0% were of indeterminate gender. The GI presented a clear annual cycle; values fluctuated but remained high (1.94-3.94) from October through April and were low (>l.50) from May through September, across both years. Across all sites, the GI had a strong, positive correlation with temperature (r = 0.783; df = 26; P KEY WORDS: black-lip oyster, Saccostrea echinata, spawning, gonad development, monsoon season, tropical, INTRODUCTION Reproduction in oysters is a cyclical physiological process, which can be continuous, semiannual, or annual; it involves several reproductive stages, including growth and ripening of gametes, spawning, resting, and [...]

The black-lip rock oyster, Saccostrea echinata, has considerable potential for aquaculture in tropical Australia and the Indo-Pacific region because of its large size, rapid growth rates, and established market acceptance. This article is the first to report on embryonic and larval development of this species reared under hatchery conditions. Developmental biology was examined across three larval cultures over a 21-day period. Newly fertilized eggs had a mean ([+ or -]SE) diameter of 50 [+ or -] 0.4 [micro]m, and postfertilization, the first polar body formed within 20 min. The earliest actively swimming trochophore appeared from 12.5 h postfertiliszation (hpf) and D-stage larvae appeared by 18 hpf. Rapid shell growth resulted in the presence of early umbo larvae at 5-7 days post fertilization (dpf). Pediveliger larvae were present from 18 dpf and the larvae settled with induction by epinephrine bitartrate from 21 dpf when they had reached an anteroposterior shell measurement of approximately 280 [micro]m and could be retained on a 200-[micro]m nylon mesh screen. Despite minor differences, overall, the early ontogeny of S. echinata is consistent with that of other members of the genus. This study fills an important knowledge gap in the literature and will aid the advancement of hatchery protocols for this developing aquaculture species. KEY WORDS: Saccostrea echinata, rock oyster, tropical, larvae, embryology, aquaculture, INTRODUCTION Tropical rock oysters have the potential to support a globally important aquaculture industry. A possible contributor to such development is the black-lip rock oyster, Saccostrea echinata, which has been [...]

As the oceans acidify, marine invertebrates will experience physiological and behavioural changes that may alter how predators interact with their prey. This study assessed whether ocean acidification alters the predatory whelk Tenguella marginalba, their prey, the Pacific oyster, Crassostrea gigas, and their interactions. Oysters and whelks were exposed separately to ambient or elevated pC[O.sub.2] for 6 weeks, after which, a reciprocal cross design was used to expose oysters and whelks together to ambient and elevated pC[O.sub.2]. Both T. marginalba and C. gigas were measured for growth, shell morphology, shell compression strength and metabolic rate. The rate at which whelks consumed oysters was also measured. We found C. gigas had weaker shells and greater SMR at elevated pC[O.sub.2], but lowered its SMR when held at ambient pC[O.sub.2] with T. marginalba. T. marginalba had a greater SMR and consumed more C. gigas when both the predator and prey were held at elevated pC[O.sub.2]. We also tested whether C. gigas responses to predator chemical cues were altered by ocean acidification. C. gigas lowered its metabolic rate in response to predator cues at ambient, but not elevated pC[O.sub.2]. We conclude that elevated pC[O.sub.2] may increase the energy requirements of predators, as they attempt to maintain homoeostasis. Furthermore, elevated pC[O.sub.2] may also alter the morphology and increase the visibility of prey. Whether the consequence of this will be a sustained increase in consumption by the predator is less certain as molluscs acclimate and the dynamics of other organisms in marine ecosystems are also altered., Introduction The unprecedented increase in the concentration of carbon dioxide (C[O.sub.2]) of the world's oceans over this century, known as ocean acidification, will impact marine organisms (IPCC 2013). It is [...]

ABSTRACT The production of toxic secondary metabolites by marine phytoplankton and their accumulation in molluscs and fish has ecosystem-wide and human health impacts. The potent neurotoxin saxitoxin and its analogs, [...]