Questions related to Fish Population Dynamics
How do we calculate theoretical age at zero length (to) in fish population dynamics? Can we take the antilog of Pauly's equation of Log (to) to calculate the same?
I plan to research the impacts (climatic and man made) of mangrove on fishery stocks. It would be wonderful if I could get some of your expert advice to make my research more precise and accurate.
For the past two years I have been collecting fin clippings of resident trout in the tarns and lakes of the English Lake District.
Surprisingly, despite the Freshwater Biological Association being on the shores of Windermere for decades not once was a comprehensive survey of the fish populations of the English Lake District ever undertaken.
There isn’t even a presence and absence survey let alone any attempt to see if there is any genetic divergence between isolated lakes and tarns populations and the semi-isolated drainage systems of the main lakes (interconnected by sea trout migration via the Irish Sea and Solway Firth).
At present, I am probably 2/3 in with two more years sampling the remainder of the stillwater bodies that I know, or suspect, contain trout in the Lake District catchment and I am seeking able bodied (some of the tarns are nearly 700m up) and / or currently practicing genetic analysts to share this study with.
The nature of the samples (frozen fin clippings) means that this is potentially a project that could involve researchers anywhere in the world. As for the field work component an interest in fishing is required and a healthy disregard to sudden inclement meteorological conditions is suggested.
I have used the 'standard' umbrella plastic anchor/dart (developed I believe by Michael Domier) for over 10 years to PAT-tag great white sharks, with much better retention of tag by shark and less or longer premature releases, than with the original titanum 'flat arrow' anchors/darts.
Now I am about to embark in the tagging of smaller fish, Mobula rays.
My question is if someone out there has been using the smaller version of the Domeier umbrella anchor/dart, the one that is 20 mm in length as opposed to the 31 mm ('standard') umbrella dart (see link below)
I am worried that this smaller version of the anchor might not have good enough retention of tags on fish. I will be using mini-PAT tags on Mobula rays that are between 1 and 2.5 m of disc width.
Any positive or negative experiences anyone can share about using the 20mm umbrella anchors for PAT tagging will be much appreciated.
Thanks in advance.
I am writing a paper that compares smolt/adult values for Chinook salmon in Redwood Cr (Humboldt Co., CA) in two recent drought years. Our smolt/adult values decreased considerably when adults could not reach the mid/upper basin. I used two DIDSON sonars (one in upper basin, one in lower basin), and 3 smolt traps. I would like to reference others who have determined smolt/adult values in other streams.
I need information for wild populations, studies where von Bertalanffy models were used. For example: one model for fish infected and one model for fish non-infected.
I am trying to model fish movement by Fishmove Package in R. There is a formula that works in this package and has tow main factor. One is mobile component of of a fish population and the second is stationary part. I know that mobile component is the part of population that migrates through river of other aquatic sources, such as estuaries of seas ( If I was right). My problem is that I can not find out what is the stationary part? It is well known that fish move and swim in it's habitat. So How it could be stable? Anyone has a clue?
Thanks in advance for your help.
Does anyone have a formula or know of a reference for converting fixed fish ovary weights (10% buffered formalinl) to fresh ovary weights for species with high fecundity? I may not be able to obtain samples for my species of interest (sablefish, Anoplopoma fimbria).
Hello everyone at RG!!
I would like your views and comments on captive breeding of Anabas testudineus.
This particular fish was available in plenty around our location in Southern India and was also a major part of diet among the locals. The fish was known to migrate from one pond to another in times of drought and could be caught doing so. Recently the population of Anabas sp has declined rapidly along with the decrease of ponds and introduction of other fishes. It would be really great if we could re-introduce Anabas sp into our ponds and freshwater canals.
If anyone had a successful farming venture, or any work on breeding them in natural/semi natural conditions; please share the information.
In 2014, a sample of a local (English) nesting fish population was caught and tagged with a unique number over a period of 6 months. During this time, fishermen would report any tagged fish they caught. Once the 2014 tagging finished, tagged fish would still be reported from as far afield as France. In 2015, the same experiment was conducted, fish were uniquely tagged and recaptures were reported. In 2015, reports of fish tagged in both 2014 and 2015 were received.
Simple population models (Lincoln-Peterson, Schnabel etc) cannot be applied to the data and I am struggling to find other models that would apply to this scenario.
There is no data on tag retention, reporting rates, recruitment/immigration, natural mortality, mortality due to fishing, etc.
I would really appreciate any advice that you can offer.
I'm interested in survival (and tag retention) estimates for Osmeridae implanted with PIT or acoustic tags, then held to see how they fare. Many thanks in advance for any information.
I mainly know of studies on the effects of plant genetics on herbivore or parasite ecology, performance, etc. What about fish-to-fish interactions, or corals to fish interactions? Is there any study tackling these issues from a genetic point of view?
I'm sampling for a specific species and to study their migration and movement, I have to catch them at several rapids.
I'm not sure if the results from different methods are comparable side by side.
Fish population dynamics:
Does there exist a publication on ratio between population and recruit yield in theory?
alternatively: does an article exist on survival rates on spawned fisheggs - in order to find such a key for a precautionay approach regarding stock management
I would like to determine the impact of climate change on fisheries. I have environmental (temperature, precipitation, etc) catch and effort data for 30 years.
We are planning to study shrimp species invasion in a bay in Japan. Our primary hypothesis about the method of invasion is through ballast water. However, it could be otherwise. Therefore could you please share your expertise to help us about the procedures, guidelines, methodologies to study marine species invasion. Thank you in advance.
Open water fisheries resources are of great ecological and economic importance. To manage these resources properly what sorts of research should be emphasized? Please share your expertise and experience.