Marine Research - Science topic

Reduction in water transport improved the water quality during lockdown

Thank you very much Tomas.

Greetings from the Galapagos Islands, Ecuador

Cheers

Francisco

Thank you very much

Hi Alex. I fear that the answer depends on what you understand by "destructive" and what are you focusing at when assessing the effects: endangered species, community-wide effects, ecosystem services, or other.

Destructive can be translated into a number of attributes as being non-selective in the target, persistent in its effects, or effective in removing individuals. From this perspective, explosives and cyanide are the less selective and effective, while ghost fishing is the most persistent and less effective.

When one comes to focusing on response variables to assess the severity of the effects, shark finning remove top predators that are both important in structuring the community, can eventually lead to the alteration of ecosystem services (for example through releasing prey fishes and thereby altering the balance between coral-dominated and algae-dominated ecosystems) and generally endangered.

Still one can put the question in the perspective of wide-scale management for conservation purposes. Then other practices like bottom trawling (cited in the previous post) and also drifting nets would have higher impacts. The former because of its spatial extent and pervasive effects through communities and ecosystems. The second because its impact on charismatic species like dolphins, whales and turtles, which raise public concern and trigger in-the-field actions.

Possibly a multivariate approach in which you combine the scores given under different criteria for each activity, tailored for the societal values rooted in your study area, would provide a more complete albeit perhaps not definitive answer.

Do you have any footage of ringed seals?

I know this person in Senegal, hope this helps :

Dr Marc BOUVY

Directeur de recherche IRD

Directeur adjoint UMR 5119, Ecologie des Systèmes marins côtiers (ECOSYM)

Université Montpellier II, Place Eugène Bataillon

Case 093, F - 34095 Montpellier cedex 5, FRANCE

e-mail: marc.bouvy@ird.fr

+33 (0) 4 67 14 41 28 (tel)

+33 (0) 4 67 14 37 19 (fax)

+33 (0) 6 13 53 24 02 (port)

Web site: http://www.ecolag.univ-montp2.fr

there is a lot of papers for sediment preparation for GC/MS measurement.

just Google it and you will find many.

but the important is to find good internal standard and start your tests.

its not hard but you need to practice it.

Dear Fatemah.

all of the responses above have value. Especially Angela's. However, you need to define the purposemore fully. Is your need ccompliance surveillance for illegal discharged across a large iceanic area or yo support spill response? Where is the area relative to satellite tracking as many are polar orbiting and so cluster near the poles for regular and frequent coverage? Do you have access to ground stations, image analysis or response systems (compliance or clean-up)?

We have recently gone through a full review and needs analysis of satellite oil spill detection and found it very enlightening. Happy to have a conversstion off line. Contact me through my work at Australian Maritime Safety Authority if need be or email paul.irving@amsa.gov.au

For spiny lobsters, colleagues of mine have used colored cable ties attached around the base of the antennae. They're easy to apply, come in multiple colors, relatively easy to identify underwater or in aquaria/mesocosms. You might be able to buy or make them fluorescent but the fluorescence signal would likely be lost underwater. The cable ties typically don't get fouled or wear off which can be a problem for some carapace marking systems.

If you're worried about loss through molting, there are a few papers that report use of sphyrion tags in lobsters. My recollection is that another paper used streamer tags to track tagged lobsters that had been released in an attempt to gauge tag loss (double tagging with streamer and sphyrion), but I haven't read these papers in a couple of years and I likely forgot some details. Try google scholar on sphyrion tag and homarus. The sphyrion tags are invasive and there is some tag loss. Moriyasu's paper indicates that mortality to tag loss isn't too high if you tag at intermolt as opposed to premolt. I think Lander's work indicates good tag retention through several molts.

I dont have a reference, but i have some suggestions.

I'll start with the fact that there is no universal method in breeding any fish including marine ornamental fishes without an understanding of the reproductive biology and environmental requirements.

First of all you have to have a species of interest, undertake a research on its ecology, habitat range, optimal salinity for mating and ionic nutrient quality of its environment, mating cues e.g. colour of female abdomen signifying gonad stage, foraging preferences and mating seasons and patterns.

When this is properly understood, laboratory trials may begin by introducing adult species from the field into culture tanks with predetermined salinity that must be sustained through some flow-through method. Mating trials may even involve the use of hormone injections to the fish but all these are subject to a thorough study on the species of interest.