Marine and Freshwater Research
Volume 67
Number 8 2016
Management procedures for high-value fisheries can be hampered by a lack of fishery-independent estimates of abundance and mortality. Traditionally these estimates have been derived in part with the use of tagging technologies. This paper provides a description of a new tagging technology which may allow managers to take advantage of fishery-independent gene tag technology within large-scale, high-throughput tagging programs.
The marine biological impact of ‘Red Dawn’ dust storm that affected eastern Australia during the spring of 2009 is examined. Dust transport modelling confirms this storm event deposited up to three times the average monthly amount of dust to the adjacent ocean. Phytoplankton biomass in the Tasman Sea increased significantly due to the atmospheric deposition of dust-associated nutrients.
Predatory scale-fish may be under pressure on a global scale due to anthropogenic forces; the legendary sciaenid Argyrosomus japonicus (mulloway, jewfish or kob) is no exception. Despite the species forming important fisheries much of its biology is poorly understood, we set out to alleviate this by investigating the genetic population structure at two levels, first, between South Africa and Australia and second, within Australia; our results report significant structuring. An understanding of the population structure of fish can help ensure a sustainable future
The neuston is a rich environment inhabited by a large variety of species. Some myctophids (mesopelagic fishes) reach this layer during their night feeding migrations, constituting an important resource competitor for the neustonic-dwelling species. Surface temperature is the main environmental variable shaping the distribution of neustonic species, whereas myctophids are also influenced by the minimum oxygen concentrations in the water column.
This study explored the benefits to a marine fish species of using both estuaries and nearshore coastal waters as nursery habitats. The abundance, growth and reproductive status of Pelates octolineatus in a large estuary are thus compared with those in marine waters. Many individuals use the estuary for an extended period and grow faster there than in coastal marine waters.
The goal of our research was to analyse the reproductive ecology and sexual system in a nocturnal seagrass shrimp. We found sex ratios support a gonochoric sexual system, seasonal breeding with successive spawns, sexual dimorphism and that the interaction of time of year, shrimp sex and parasite presence influenced shrimp size. This data support hypotheses about latitudinal trends in other marine species.
The California spiny lobster is an ecologically and economically important species on southern California rocky reefs. We used manipulative experiments to determine how sheltering behaviors observed on naturally-occurring reefs influence the survival of subadult lobsters. Our study is the first to demonstrate the survival benefit of selecting shelters based on the size, and not just the presence, of other lobsters.
Paralytic shellfish poisoning (PSP) occurs when people consume shellfish containing algal toxins known as saxitoxins. Both surf clams and green-lipped mussels readily accumulate these toxins. After 8 days of detoxification, toxin concentrations in the mussels had fallen, but in the clams, concentrations remained higher than was safe for human consumption. Mussels and clams can therefore be used to monitor the health risks associated with toxic algal blooms.
Understanding what factors determine the number and type of fish on coral reefs is important for effective management of these fragile systems. In this study, we compared the effects of habitat and predation on two major feeding types of butterflyfish, and found that live coral and macroalgae were the strongest determinants of butterflyfish abundance. These results encourage wider-scale management of coral reefs to promote coral health.
Effective estuarine management depends on adequate data about habitats. This study presents the first quantitative assessment of subtidal habitats within the Port Stephens estuary, using a methodology that was cost-effective and robust. We identified previously undocumented habitat types and found strong correlations between habitat types and depth.
As a top predator, the platypus has the potential to exert a strong top-down influence within riverine food webs. We utilised a combination of cheek pouch content analysis and stable isotope analysis to determine the platypuses' diet. Whereas the cheek-pouch content analysis identified the majority of the prey organisms, stable isotope analysis suggested that soft-bodied organisms (e.g. larval dipterans) are also a strong contributor to the platypuses' diet.
Highly migratory marine fishes are often assumed to lack population structure due to the absence of physical barriers to gene flow. We used genetic markers to evaluate the population structure of the black marlin throughout the central Indo-Pacific. The nuclear markers revealed three contemporary populations that are likely driven by reproductive philopatry, whereas the mitochondrial markers identified pronounced historic clade structure.
Epinephelus daemelii is a threatened grouper species restricted to the south-western Pacific Ocean. Its biology, behaviour and limited habitat make it vulnerable to overfishing. Despite protection, incidental bycatch still occurs. Its abundance is low, except in remote regions with no fishing. Further prohibitions on fishing are likely to be important for the recovery and long-term survival of this species.
The aim of the present study was to determine the distribution and migration of twaite and allis shad in the north-west of the Iberian Peninsula. To this end, official data records of marine landings were collected and freshwater field sampling campaigns were undertaken. Results show that both species exhibit a coastal distribution near the rivers where they spawn, namely the Minho and Ulla rivers.
The mitochondrial genome of Bugula neritina sampled from Qingdao, China, was determined, and was compared with that of a specimen sampled from Taean Gun, South Korea. The results indicated that the two specimens are genetically distinct species. The new type from Qingdao is designated as Type Y, for its occurrence in the Yellow Sea. The geographical range of different types of B. neritina awaits further studies.
Coral diseases have been poorly studied in the Indian Ocean, and particularly in the Republic of Maldives. The results of this study represent the first comprehensive assessment of coral diseases in this archipelago and provide a useful baseline that can serve as a gauge for monitoring future change. The study reveals that large colonies are more susceptible to coral diseases than small ones, and that the dominant genus Acropora hosts the highest number of diseased colonies.
Despite being critically endangered, the behaviour of hawksbill turtles remains poorly understood, especially for populations nesting in the Northern Territory, Australia. Satellite telemetry showed that adult females remain close to their rookery during the breeding period before migrating to feed in the Gulf of Carpentaria. National and international conservation efforts are required to mitigate human impacts including illegal tortoiseshell trade or seabed mining exploitation.