The Open Fish Science Journal

Rapid Lateral Extraction of Otoliths that Maintains the Integrity of Fish Product to Improve Access to Catches and Reduce Potential Sampling Biases
The capacity to sample otoliths of fish from commercial, recreational, artisanal or subsistence catches can be constrained if the dissection process results in alterations to their external appearance and thus reduces its value and/or shelf life. There can also be significant biases incorporated into the collection of otolith samples if access is only granted relative to the size of the fish (i.e. if smaller fish are sold whole)..
Exploring the Biological Basis of Age-Specific Return Variability of Chinook Salmon (Oncorhynchus tshawytscha) From the Robertson Creek Hatchery, British Columbia Using Biological or Physical Oceanographic Explanatory Variables
We used information about hatchery rearing and release practices for 173 releases of age 0+ smolts between 1982 and 2012, as well as time series of early marine prey biomass and predator abundance/biomass, to investigate the biological basis of age-specific return variability of chinook salmon (Oncorhynchus tshawytscha) from the Robertson Creek Hatchery..
Do You Eat or Not? Predation Behaviour of European Catfish (Silurus glanis) Toward Live Bait on a Hook
We filmed and analysed, in natural and field conditions, behaviours of large-bodied European catfish (Silurus glanis) individuals (body size ranging from 80 to 220 cm) exposed to a hook baited with 20 cm-long Carassius spp.
When Do Mountain Whitefish (Prosopium williamsoni) Spawn? A Comparison of Estimates Based on Gonadosomatic Indices and Spawner and Egg Counts
Determining when fish spawn has major implications for effective fisheries management, particularly in dam-controlled rivers where reproductive potential may be affected by an altered hydrograph. Three methods for estimating spawn timing in riverine broadcast spawners were compared for their precision, effort and potential impact on a population of Mountain Whitefish in the regulated Lower Duncan River, Canada.

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31-March 2017Read More...

Editor's Choice

An Overview of the Current Status of Lake Naivasha Fishery: Challenges and Management Strategies

James Njiru, Edna Waithaka, Peninah A. Aloo

Lake Naivasha a shallow, freshwater body and a Ramsar site is found in the eastern arm of the Kenyan Rift Valley. This paper used published, unpublished and analyzed data to assess the status, challenges and management options for the fishery. Lake Naivasha fishery is based on exotic species that fluctuates depending on fishing regime, lake water level and aquatic plant concentrations. The fishery has been dominated by different species with the current catch contribution consisting mainly of common carp, Cyprinus carpio, Nile tilapia, Oreochromis niloticus, blue-spotted tilapia, O. leucostictus and African catfish, Clarias gariepinus. The minimum and maximum catch of 21 t yr^-1 and 1181 t yr^-1 was reported in 1997 and 2015, respectively. The main threats to the lake fishery are anthropogenic influences emanating from within the lake and its basin. The factors include intense fishing, exotic species introductions, water abstraction, lake level fluctuations, wetland utilization, eutrophication, and land degradation. There are also several conflicts of interest amongst the stakeholders in agriculture, fisheries, wildlife, tourism, conservation and geothermal electricity generation. There is fear that if the current trend persists, the lake and its fishery may be headed for extinction. The management measures instituted in the lake do not seem to have arrested reduction in fish catches nor reversed deterioration in water quality. For sustainable utilization of Lake Naivasha and its fishery, there is a need to consider a holistic ecosystem approach of the basin management. Additionally, all the relevant stakeholders should be involved in formulation and implementation of the decisions to manage the fishery.

March 31, 2017