The Fish Ecology
Our appreciation of the ecological importance of fish will begin by understanding how and where fish life could likely exist. Any reference to fish life includes sharks, rays, lampreys, chimeras, hagfish and lungfish, albeit jawless marine vertebrates.
The ecological structure of fish communities depends on the kind of aquatic habitat and environment in which they move around and subsist. Various fish types exist in almost all possible and habitable water realms.
Fish ecology is described as the entire system by which fish life exists as a pelagic inhabitant. The term pelagic refers to matters associated with the sea or body of water without any specific requirement about the depth of the water realm.
Coastal areas provide the ideal location for fish life to flourish. These are parts of the sea, where the nutrients coming from the bottom of the ocean are deposited, as they are brought up by the natural flowing movements of the oceans and seas.
These nutrients provide nourishment for the phytoplankton, which are microscopic marine organisms, usually in a bacterial form or as single-celled plant life, and they represent the basic link in an aquatic ecology’s food chain.
Other fish habitats can be found in nektonic areas of the ocean where nekton organisms survive as they actively move and swim in bodies of water like the ocean or lakes. . The nekton’s role in the marine food chain varies because they come in different sizes; a nekton could be as short as few centimeters or be as long as 30 meters. Hence, nektons to a fish community could be prey or predator.
They can be represented by shrimps, squids, octopus, sharks and humpback whales, and because they have distinct methods of swimming, they have the ability to migrate even amidst strong ocean currents.
Fish who flourish in the deepest parts of the ocean rely on benthic organisms or benthos as their basic food stores. Benthic habitats also exist in near shore or estuarine zones at less than 200 meters deep, like the coral reefs, kelp forests, seagrass or eelgrass beds.
This is where the benthos organism like hard clams, mussels and bay scallops could find shelter and protection against the buffering waves. However, the types of benthos that provide food for the fish community are the worms, plants and the shrimp-like amphipods.
Now that we know where fish ecology likely exists, their subsistence and environmental characteristics, we can proceed with our brief study of the ecological importance of fish.
Fish: Their Ecological Importance
Coastal communities are the first to benefit from the different fish species that forage for food in estuaries, marshes, wetlands, mangroves and bay areas. Mankind’s creator designed the aquatic ecosystem in such a way that food can be provided in areas that are more accessible.
However, human beings found more uses for marine life aside from their function in the food chain. The demand for fish supply became greater than what was preordained. Different types of fisheries were developed and came to be known as “capture fisheries”. The fishing activities are further sub-categorized by the species captured, by the gears used and by the size of the industry, whether in small or industrial scales. By these alone, we could form an idea as to how extensive the demand for fish life came to be.
In fact, human beings developed such an extra-ordinary liking for fishing activities that fish-catching became a source of recreation. Coastal communities largely encouraged their visitors to engage in recreational fishing because it brought them additional sources of income. Inns, cottages, campsites, real estate properties flourished, souvenir shops and fishing-gears stores mushroomed, diners, restaurants and water parks and all sorts of income-generating businesses were established.
Soon enough, families came in hordes as they found likely spots where they could spend their vacation and engage in other water activities aside from fishing. They could surf, wakeboard, water ski, race in power boats, or explore the deeper parts of the ocean via snorkeling or scuba diving.
In doing the last two, they came to discover a diversity of colorful and interesting marine lives in existence, which led to their cravings to own and bring home these creatures as well. However, the cravings turned into another form of livelihood because the exotic fish species were quite attractive as habitués in aquariums and exhibits.
Whereas formerly man was content with a single goldfish in a bowl or several in a man-made pond, aquariums became the popular modern concept as technologies were developed to create artificial fish ecology in glass tanks of different sizes.
Fish: More Examples of Their Ecological Importance
Other sectors of the fishing industry found more uses for different fish parts and are enumerated as follows:
The fish scales were developed into raw materials for artificial pearls and decorative beads.
The fish substance known as isinglass derived from the air bladders of a fish became an important raw material for glue production because of their gelatinous consistency.
The fish offal or the fish trimmings like the heads or fish bones was rich in protein and its use went beyond culinary purposes, as different fish types contained different levels of nutrients. They could be used as fish meal or converted into fish silage.
Fish silages are whole or fish parts converted into liquid form and used as additional ingredients for animal feeds.
Unsold or surplus fish were also industrially composted to produce nitrogenous fertilizers.
The oil extracted from fish livers are good sources of Vitamin D while whales are providers of blubber oil.
These are only the most popular uses of fish; it could expand even more as different chemicals are combined to exploit the rich nutrients or even the toxic substances found in various fish species. However, the ecological importance of fish life was overlooked as mankind’s demand became even greater.
Perhaps, the word exploit is an understatement as we continue to bring our discussion to the many problems that beset the ecological structure of aquatic life as a whole.
The Problems that Beset the Fish Ecology
The massive demand for fish led to over-exploitation in such dimensions that it caused the depletion of fish supply not only in coastal and near shore areas.but in the deeper regions as well. Water pollution coming from all sources affected the entire vastness of the ocean.
Floods, garbage, polluted water run-offs, oil spills, sunscreen wash-offs, chemical dumping and even ocean acidification all contribute to the contamination as well as eutrophication of the water where fish ecology could survive.
As technology advanced, so did mankind’s water activities. Large fishing vessels for one, make use of trawls and dredges that scrape the bottom of the sea, in order to catch as many as several tons of fish in just a single fishing expedition. The rapid dwindling of fish life was aggravated by tons of non-targeted fish being thrown back to sea as discards; they merely spoil or rot and become unfit even as fish meals.
Other methods of fishing make use of explosives and could, likewise, cause the unnecessary deaths of thousands of marine creatures left dying in the ocean floor.
As observers had predicted, the total lack of concern for the ecological importance of fish and other marine lives led to the extinction of several species as well as the widespread endangerment of many more.
The Impacts of Fish Ecology Degradation and Destruction
To briefly discuss the impact of fish ecology degradation and destruction, we’ll use as an example the salmon fish type, which previously held a record of 1,400 salmonid populations. Today, 29% of these salmon species, including pink salmon, had disappeared and are believed to have become extinct. This led to a coast wide closure of fisheries in the Northwest Pacific.
The once bustling coastal communities are now suffering from the ecological degradation of their coastal areas. Government regulations and restrictions have been instituted as attempts to recover the loss of these natural resources.
The dollar values of community losses are placed at an annual figure of $10 to $20 billions, and that long-term efforts have been undertaken to restore the once abundant salmon population. However, researchers still have a long way to go since results prove that this fish species does not respond well to controlled environments.
The impacts of fish habitat destruction and fish decline have been noted on a global scale not only in America. Based on the conclusions drawn by the researchers from their studies of the ecological importance of fish, the entire aquatic ecosystem has limited capacity for self-restructuring following ecological disturbances. This is one reason why fish supply could not meet the extensive demand.
Hence, there are urgent calls for human actions to prevent and eventually eliminate all possible sources of ecological disruption. Otherwise, we are warned of more fish extinctions and the high probability of food shortage.
Reference Materials and Image Credit Section
- Aquatic and Related Terrestrial Ecosystems — https://books.nap.edu/openbook.php?record_id=11139&page=59
- Cumulative Effects of Coastal Habitat Alterations on Fishery Resources: toward Prediction at Regional Scales — https://www.ecologyandsociety.org/vol14/iss1/art16/
- Population and the Environment: The Global Challenge Excerpts from a Johns Hopkins University report —https://www.actionbioscience.org/environment/hinrichsen_robey.html
- All Images are Courtesy of Wikimedia