Marine and Freshwater Research
Volume 75
Number 2 2024
As a productive coastal lake, Te Waihora–Lake Ellesmere could potentially support a range of fisheries. However, because of its irregular opening schedule driven by flood management and severe environmental degradation, a persistent population of the widespread diadromous galaxiid, Galaxias maculatus, was unable to form within the lake and its network of tributaries.
Improving fish passage is essential for the recovery of freshwater biodiversity. Mark–recapture methods are often used to measure the effectiveness of efforts to restore river connectivity. This study shows that the method used to mark fish can significantly affect estimates of passage efficiency for a small-bodied fish that is distributed widely in the Southern Hemisphere.
Pelagic longline fisheries developed bycatch mitigation measures, replacing J/tuna hooks and squid bait with circle hooks and whole-fish bait to reduce sea turtle bycatch. However, they overlooked the effects on other endangered species. Long-term data showed that circle hooks increased mouth-hooking in both target and bycatch species, proportional to their size. Although circle hooks with squid bait did not increase fishing mortality per unit effort (MPUE) for shortfin mako sharks, combining to whole-fish bait significantly increased MPUE. It highlights the need for quantitative assessments before implementing bycatch mitigation measures.
The Pacific nurse shark (Ginglymostoma unami) is an endangered species with a restricted distribution from Baja California to Perú. Although the movement ecology of Atlantic nurse sharks (G. cirratum) has been widely studied, this is the first attempt to describe a long-distance dispersal by the Pacific nurse shark. Using acoustic telemetry, we report the longest distance movement observed for the species. A male shark was observed travelling up to 460 km in 46 days along the Pacific coast of Costa Rica.
Establishing the relationships between frogs and river flows that fill wetlands is important to guide the management of environmental water. Our study focused on the influence of flow and habitat on wetland frog breeding activity and breeding success. Although large areas of inundated wetland support high numbers of calling male frogs, wetlands also need sufficiently long inundation duration to increase breeding success.
This article belongs to the collection Environmental flows in northern Murray–Darling Basin: what we know about the science and management after a decade of practice.
In this study, a multifactor and multilayer comprehensive early risk-warning method was established to improve the timeliness and accuracy of risk warning for nuclear power plant operation under the stress of Phaeocystis globosa blooms.
This article belongs to the collection Ecological Monitoring and Assessment of Freshwater Ecosystems.
, Michael J. H. Hickford 
