Prepared by: Brian S. Sheridan

Course:
BIOL181: Life in the Oceans

Assignment:
Written Assignment 1 – The Spanish Mackerel

Date:
02/18/2012

Physical Description and Habitat -
In the Atlantic Ocean there are three fish groups of Mackerel. The (Scomberomorus maculatus) or more commonly referred to as the Spanish mackerel are “mid-level pelagic carnivores” (noaa.gov) that have closely related cousins. The other types of mackerel that are related to the Spanish are the larger but less spotted King mackerel (Scomberomorus cavalla) - and the (Scomberomorus regalis) known as the Cero mackerel. All types of mackerel are migratory pelagic fish. They inhabit, feed and spawn in areas of the Atlantic spanning from the Gulf of Mexico to Northern parts of the eastern United States. Although there are subtle differences between the three types, this paper will focus mainly on the Spanish mackerel. The male and female Spanish mackerels vary in size. The male usually averages out to a length of about nineteen inches while the larger sized female mackerel can grow as long as thirty three inches (Wikipedia). The Spanish mackerel’s are a stunningly colored fish. They are mainly silver from its head to tail, however the upper back almost glows green, while its sides have layered yellow spots, standing out further due to its mainly black shaded dorsal fin and tail. Mainly looking for prey the mackerel tends to stay in shallower water, sometimes noticed snorkelers and or scuba diving alike close to the shore. Although mackerels growth rate is extremely up to four years of age and then hold steady each year thereafter. Both the male and female are capable of reproduction after their second year of life. Most mackerels don’t live much past 12-13 years of age.

Reproductive Behavior –
Spanish mackerels are considered to be “batch spawners” (NOAA.gov). This means that during a mackerels spawning season they lay eggs more than once. Most of the spawning for Spanish mackerels occurs in the waters of the eastern US off of Cape Hatteras North Carolina and the coast of Virginia. In the Gulf of Mexico they swim up close to shore to shed their eggs. Other testing results have been more detailed in which a time period was discovered where Spanish mackerel’s reproduction period was greater. In an article written by Mark Collins and Bruce Stender, in which ichthyoplankton data was collected by the University of Miami between the years 1973-1980 the reproductive habits of Spanish mackerel was very telling. The research revealed spawning habits of the mackerels between were at their highest from May through September at depths “less than 40 meters” (Collins &, Stender).
Feeding Behavior –
Overall the Spanish mackerel is a highly opportunistic hunter known for its large appetite. Most young Spanish mackerel feed on a couple different types of other fish species. A young mackerels diet consists mostly include carangids (Jacks & Pompanos), clupeids (small marine boney fish i.e. a Wolf Herring) and engraulids (Anchovies). However, as Spanish mackerels mature their diets change. In an article released by the U.S. Army Corp of Engineers written by Mark Godcharles and Michael Murphy it states that “squid was the major invertebrate prey for both species of adult mackerel both the King and Spanish”. Other types of fish that mackerels consume are shrimp, crab, needlefish, ribbonfish and menhaden. As a predator of smaller fish than themselves, Spanish mackerels are constantly preyed upon by Sharks and Dolphins.
Migratory behavior –
Mostly the Spanish mackerel travels in schools when migrating and move up the east coast northward and then back to the south (florida-outdoors.com). The Spanish mackerel travels a fair amount of distance during its lifetime. The main Atlantic Group migrates along the Atlantic Coast of the United States from Florida beginning in Late February through July reaching as far as Cape Cod Massachusetts.
Use by Humans –
Spanish mackerel are mostly caught as “bycatch” in nets used to land wild shrimp in the southeastern United States (apps.edf.org). While Spanish mackerel is edible it is high in cholesterol and fat (6.2 grams per serving). There have even been warnings of high mercury levels contained within the fish. But mackerel does have redeeming values for consumption they are high in niacin and selenium. When on a moderate diet of Spanish mackerel meaning adding it occasionally to your diet and prepared the manner of choice it is a good source vitamin B6 and B12 and its low in sodium (nutritiondata.self.com). Outside of the fact that Spanish mackerel does have nutritional value they are also targeted for recreational and charter fishing expeditions. The amount of fish that can be expected to be caught during a fishing trip greatly varies day-to-day due to their migration.

Susceptibility to Human Activities –
Most of the Spanish mackerel landings have come from commercial fisheries. In fishing terms, “Landings”, simply put is the amount of fish that is brought back to land (noaa.gov). It has been noted that during the late since the 1970’s and through the early 1980’s the statistics have shown that Spanish mackerel catch has been steady. The troubling aspect of the NOAA’s data is that the catch numbers were consistently greater in time periods prior the 1970’s. The amount of catch that fisherman are landing today is significantly less than they were landing 35-40 years ago. According to (Martins, M. 2007) catch numbers averaged between 3200 – 7200 tons starting from 1986 to 2003.

Though environmental and market preferences may play a role in Biomass and Landings data collection efforts overall catch numbers have gone down. Even though it is believed that the Spanish mackerel numbers are high and overfishing is “not occurring” (noaa.gov) Spanish mackerel play an important role in the survival of humans and other marine animals. The good news is that according the National Oceanic and Atmospheric Administration Spanish mackerel are “above the biomass needed to support maximum sustainable yield (BMSY).” This means although the overall catch numbers have dwindled, the Spanish mackerel are naturally sustaining themselves and there is currently no need to stop catching this type of fish.

References 1. Martins, M. (2007). “Growth variability in Atlantic mackerel (Scomber scombrus) and Spanish mackerel (Scomber japonicus) off Portugal”. ICES Journal Of Marine Science / Journal Du Conseil, 64(9), 1785-1790. doi:10.1093/icesjms/fsm163

2. Authors: Collins, Mark R.; Stender, Bruce W. Source: “Bulletin of Marine Science, Volume 41, Number 3, November 1987, pp. 822-834(13)”. Publisher: University of Miami - Rosenstiel School of Marine and Atmospheric Science

3. Godcharles, Mark, F. & Murphy, Michael, D. “Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Florida) KING AND SPANISH MACKERAL”. U.S. Fish and Wildlife Service Biological Report 82 (11.58) Published by the U.S Department of Interior U. S. Army Corps of Engineers 1986

4. Web: http://www.nmfs.noaa.gov/fishwatch/species/spanish_mack.htm. May 3rd 2011.

5. Web: http://nutritiondata.self.com/facts/finfish-and-shellfish-products/4077/2. February 17th 2012

6. Web: http://apps.edf.org/page.cfm?tagID=15841. February 17th 2012

7. Web: http://www.florida-outdoors.com/fsspan.htm. February 17th 2012

8. Web: http://en.wikipedia.org/wiki/Scomberomorus_maculatus. February 17th 2012