Lutjanus

Weber, Cécile, 2024, Taxonomic Review of Genus Lutjanus (Perciformes Lutjanidae): Species Delimitation and Phylogenetic Insights, FishTaxa 34, pp. 1-11 : 6-9

Ecological Importance

Predator Role

Snappers are a staple component of predatory ecosystems within the marine habitat due to their capability to control the preyed species' population. This makes it easier to moderate the populations of small fish hence preserving the conditions of reefs by avoiding overgrazing by algae. Animal carcasses are an unheralded but ASM crucial food and nutrient source for animals and plants," said co-author Joseph Bump, a professor at the University of Minnesota College of Food, Agricultural, and Natural Resource Sciences. Cougars, bears and wolves, being the principal predators, have a signature of when, where and how many carcasses there are in a particular ecosystem at a given time of the year despite the fact that animals die and their carcasses hit the ground all year round from various causes of mortality such as diseases and human hunting. The researchers also point out that it is critical to define all the functions that predatory species perform and preserve populations of such species and their prey. "People like to believe that they can replace predators, and thus, it is probably fine to have some places without large predators," explained Sean Johnson-Bice, the author of the study and a Ph.D. candidate at the University of Manitoba. "However, our work shows that there is such a range and variety of how a single individual predator influences the system that we could never realistically mimic the presence of the predators in ecosystems. The authors of the research hope that the study may help improve the conservation and the population management of many predators globally, which are declining due to factors such as habitat loss, human interference, hunting and poaching, and climate change ( Figure 1 ).

Habitat Association

Snappers are a staple component of predatory ecosystems within the marine habitat due to their ability to control the preyed species' population. This makes it easier to moderate the populations of small fish hence preserving the conditions of reefs by avoiding overgrazing by algae. Animal carcasses are an unheralded but ASM crucial food and nutrient source for animals and plants," said co-author Joseph Bump, a professor at the University of Minnesota College of Food, Agricultural, and Natural Resource Sciences. Cougars, bears and wolves being the principal predators, have a signature of when, where and how many carcasses there are in a particular ecosystem at a given time of the year despite the fact that animals die and their carcasses hit the ground all year round from various causes of mortality such as diseases and human hunting. The researchers also point out that it is critical to define all the functions that predatory species perform and preserve populations of such species and their prey. "People like to believe that they can replace predators, and thus, it is probably fine to have some places without large predators," explained Sean Johnson-Bice, the author of the study and a Ph.D. candidate at the University of Manitoba. "However, our work shows that there is such a range and variety of how a single individual predator influences the system that we could never realistically mimic the presence of the predators in ecosystems. The authors of the research hope that the study may help improve the conservation and the population management of many predators globally, which are declining due to factors such as habitat loss, human interference, hunting and poaching, and climate change.

Commercial Fisheries

Commercial fishing is harvesting fish and other seafood species for profit, mostly from stocks in the wild. The industry offers a significant amount of food to many countries across the globe, but those who exercise it as an industry in mind have to, in many cases, seek the in the deep sea under rather unpleasant weather conditions. Industrial fishing is defined as mass or commercial fishing ( Figure 2 ). Major industries of the fishing sector are big corporate companies and families. To enhance revenue from the reduced fish populations and the prevailing demand, some commercial fishing companies have lowered the sustainability of the catch by targeting species in the lower order. This is worrying for fishery managers and researchers, as they continue to point out, they say that for those reasons, the sustainability of the marine ecosystems is at risk of hitting the wall. They catch numerous of species usually associated with commercial fishing. Yet, most of the world's fish stocks are derived from a very limited number of species; herring, cods, anchovy, tuna, flounders, mullets, squids, shrimps, salmon, crabs, lobsters, oyster and scallops. All but these last four yielded a world catch of over one million metric tonnes in 1999 and together herring and sardines accounted for 22 095 963 metric tonnes of the total catch in 1999. Other species are other fished in a less proportionate manner. Of the total global fish production in 2016 of 171 million tonnes, more than 151 million tonnes or 88 percent of the catch were used for human consumption. This share has raised even in the recent decades, and from the 1960’s it was 67 percent. Of the 12 percent utilized for non-food uses in 2016, the highest proportion, about 74 percent or 15 million tonnes, was processed to fishmeal and fish oil while the majority of the 5 million tonnes was directly used as material for feeding in aquaculture, raising of livestock and fur animals or cultured fish fry, fingerlings or small adults for on growing, as bait or for use in the pharmaceutical industries and as ornaments.

Fishing Methods

They are also frequently captured through line fishing, traps and including netting. They are popular fishing destinations, and therefore attract fishing activities, both national and international ( Figure 3 ). Fishing methods are strategies used to fish. The term may also be used in respect of techniques for capturing other water creatures including mollusks (bivalves, cephalopods, gastropods), and other edible marine invertebrates. Gathering which entails chasing the target animals and catching them using the bare hands is another method of fishing practicing today spear fishing, netting, angling and trapping are also forms of fishing. angling Articles and fishers employ distinct equipment’s and methods of fish, catching recreation, commercial and artisanal fishers use different techniques and at times the same ones. One more can be distinguished between the recreational fishers that fish merely for fun or as a sport and commercial fishers that fish for business. Small scale fishers employ rudimentary equipment since they operate in less developed societies or out of cultural ethnic practices in other societies. Mainly, sport fishers practice angling techniques, while gear fishers– commercial fishers, employ netting techniques. It becomes quite easy to unravel that there is a complex relationship between different methods of fishing and information on the fish and their activities such as migration, feeding and their preferred habitats. Lack of this additional knowledge can hamper the successful application of methods of fishing. That is, it is still possible to note that which techniques are appropriate is defined mainly by the target species and by its dwelling place. There is a difference between fishing techniques and fishing tackle. Tackle is the equipment used in fishing while techniques is the way, method or approach used while fishing.

Cultural Significance

In the Burra Charter context cultural significance refers to something that is of ‘emotional, historical, scientific or social significance for the past, the present or the future generations. Cultural importance is a theory that can assist in making out the worth of areas. The most interpretations could single out the place that was useful in orientation with the past or valuable in the contemporary world and beneficial to the future community. The meaning of these terms as well in relation to cultural importance include Aesthetic value that includes those characteristics of sensory appreciation for which criteria formula, size, color, surface texture, style and material used in fabric is relevant; Historic value which encompasses things done by historical personalities, events, periods and processes. Where there is in-situ documentation of an association or event, or the setting remains principally undisturbed, significance should be rated higher in this category than in cases where the setting has been altered and the evidence obliterated. Credible scientific value refers to the research capability of a specific area or the extent to which a particular area is able to contribute more to an understanding of an area. Social value supports the attributes which make a place an object of the spiritual, political, national and or other culture identity and one that, with equal measure, has value to a particular local or larger social group. The division into aesthetic, historical, scientific and social significance is always modified by the frequency of the item in the given category. Spiritual value is one of the newest additions to the framework of Burra Charter as it falls under things that are formally intangible or non-material.

Species Delimitation and Phylogenetic Insights

Many earlier attempts to differentiate species within the genus Lutjanus have been based on morphological features such as meristic count, color patterns and body shape ( Figure 4 ). However, the genus has several cumbersome factors including inherent variability, similar physical characters, and merely concealed species. Such factors distort a classical matrix and make it difficult to accomplish a definite taxonomical decision and avoid a mistake. In the years of effective molecular phylogenetics, the necessary information for the elucidation of the evolutionary trends in Lutjanus has been elicited. Mitochondrial loci include the cytochrome C oxidase I gene (COI), the cytochrome b gene (Cyt b), and nuclear markers such as the internal transcribed spacer (ITS) region and the 7th intron of the evolutionarily conserved gene S7, which have widely been used in molecular taxonomy and DNA barcoding for delimitation of genetic lineages. Some synchronic variants are shown to have arisen through cryptic speciation and phylogenetic affinities concerning the contacts of morphological convergence had been industrialized. A combination of molecular and conventional taxonomic morphology and ecology has been developed into a useful framework for species identification. These methodologies have identified different subpopulations within otherwise widespread species; therefore, may be suggesting underestimation of species richness in the genus. For instance, molecular analyses have recognized separate cryptic species in the Lutjanus flimflammer species groups, showing the value of gene-based procedures to expose previously overlooked richness. Further, the phylogenetic analysis has revealed much about the evolutionary processes of the genus, including a biogeographical history proposed due to dispersal-vicariance. These findings further amplify the knowledge of the diversification patterns and special adaptations of this genus in different marine ecosystems. Nevertheless, there are still important gaps in the existing knowledge concerning this subject. The need for further taxonomic work involves sequencing an entire genome of observed species, sampling more broadly across the genus’ geographic range, and investigating more details of other ecological and behavioral characteristics to achieve the finer species clarification and clarify the evolutionary relationships. Closing these gaps will lead to improved taxonomic assessments for the species and help in the overall conservation and management of the species, due to its importance in economy and ecology.

Figures

Figure 1: Ecological Importance

Figure 2: Commercial Fisheries

Figure 3: Fishing Methods

Figure 4: Species Delimitation and Phylogenetic Insights