Menhaden: Everything You Need to Know About Brevoortia spp. and Ethmidium spp.

What is Menhaden?

Menhaden (Brevoortia spp. and Ethmidium spp.) are small, filter-feeding fish belonging to the Clupeidae family, including sardines, herring, and shad. These silvery, schooling fish are considered vital components of marine food webs and contribute to the health of coastal ecosystems through their unique feeding habits and role as a forage species for numerous predators.

Taxonomy and Morphology

Menhaden are classified into two genera, Brevoortia and Ethmidium, each comprising multiple species. The most well-known species is the Atlantic menhaden (Brevoortia tyrannus), which inhabits the western Atlantic Ocean. These fish typically grow to 12-15 inches (30-38 cm) and have a laterally compressed body. Menhaden possess a large, terminal mouth equipped with gill rakers that enable filter-feeding, a key adaptation for their ecological role.

What do Menhaden Eat?

Menhaden are filter-feeding fish that primarily consume phytoplankton and zooplankton. Phytoplankton are microscopic, photosynthetic organisms that include algae, diatoms, and cyanobacteria, which form the base of many aquatic food webs. Zooplankton are small, drifting organisms that feed on phytoplankton and, in turn, serve as a food source for larger aquatic animals. By consuming phytoplankton and zooplankton, menhaden play a crucial role in transferring energy and nutrients from lower to higher trophic levels in marine ecosystems.

Life Cycle and Reproduction

Menhaden are anadromous, spawning in estuarine and nearshore marine environments before migrating to freshwater systems as juveniles. Spawning typically occurs from late fall to early spring, with females releasing hundreds of thousands of eggs into the water column. 

The fertilized eggs develop into planktonic larvae, eventually metamorphosing into juveniles as they settle in nursery habitats. Juvenile menhaden then migrate to freshwater systems where they grow and mature for two to three years before returning to marine environments to spawn, completing their life cycle.

Distribution and Habitat

Menhaden inhabit the coastal waters of the western Atlantic, ranging from Nova Scotia, Canada, to northern Florida in the United States. They are also found along the Gulf of Mexico’s coastline, particularly in estuaries and nearshore environments. Menhaden prefer temperate waters; seasonal temperature fluctuations and oceanographic conditions influence their distribution.

Ecological Significance

Menhaden play a critical role in marine ecosystems as forage species, providing a vital link between lower and higher trophic levels. They feed on phytoplankton and zooplankton, converting primary production into a consumable resource for numerous predators, including larger fish, birds, and marine mammals. Menhaden are also crucial in nutrient cycling, as their filter-feeding activities remove excess nutrients from the water column, helping maintain water quality and prevent eutrophication.

How to Catch Menhaden

Catching menhaden can be done through a variety of methods, depending on the scale of the fishing operation and the intended purpose (e.g., recreational or commercial). Some common techniques for catching menhaden include:

1. Cast netting: This method is popular among recreational anglers and involves using a circular net with weights along the edges. The angler tosses the cast net over a school of menhaden, allowing the weights to sink and encircle the fish. The angler then retrieves the net, trapping the fish inside. This technique requires skill and practice to perfect the throw and ensure a successful catch.
2. Purse seining: This method is commonly used in commercial fishing operations. A large net called a purse seine, is deployed around a school of menhaden by a fishing vessel. The bottom of the net is then drawn together like a purse, enclosing the fish within. The net is hauled back onto the vessel, and the trapped fish are collected. Purse seining allows for the capture of large quantities of fish, making it efficient for commercial purposes.
3. Gillnetting: Gillnets are long, vertical panels of netting suspended in the water column by floats and weights. Menhaden swim into the net and become entangled by their gills. This method can be used for both commercial and recreational fishing. However, gillnetting has the potential for bycatch, capturing non-target species and posing a threat to marine ecosystems.
4. Bait and hook: Although not the most efficient method for catching menhaden, a small hook and bait can be successful. Anglers can use a light tackle setup and small hooks, typically size 8 or 10, baited with small pieces of shrimp or other fish. This technique suits recreational fishing or catching live bait for larger game fish.

When catching menhaden, it’s essential to follow local regulations and guidelines to ensure sustainable fishing practices and minimize the impact on menhaden populations and the ecosystems they support.

Can you eat Menhaden?

While menhaden are technically edible, they are not commonly consumed by humans due to their strong, oily taste and high levels of bones. Menhaden are rich in omega-3 fatty acids, which provide numerous health benefits. Still, their flavour profile and bony texture make them less desirable for direct human consumption compared to other fish species like salmon, tuna, or cod.

What is Menhaden Fish Meal?

Menhaden fish meal is a high-quality protein feed ingredient from processed menhaden fish. Production involves cooking, pressing, drying, and grinding menhaden into a fine powder. Fish meal is rich in essential amino acids, minerals, and vitamins, making it a valuable nutritional supplement in animal feed.

Menhaden fish meal is particularly popular in the aquaculture industry. It is used as a primary ingredient in feed for various fish species and crustaceans, such as salmon, shrimp, and other farmed aquatic organisms. Its high protein content and balanced amino acid profile promote these animals’ growth, health, and overall performance.

Besides aquaculture, menhaden fish meal is also utilized in the feeds of poultry, swine, and other livestock, contributing to producing high-quality meat, eggs, and dairy products. However, due to concerns about sustainability and overfishing, the aquaculture industry is increasingly seeking alternative protein sources, such as plant-based proteins, insects, and single-cell proteins, to reduce dependence on fish meal.

Human Impact and Conservation

Menhaden have faced various challenges due to human activities, including overfishing, habitat degradation, and pollution. These factors have led to population declines and raised concerns about their ecological role in coastal ecosystems. Conservation measures, such as sustainable fisheries management and habitat restoration, are being implemented to safeguard menhaden populations and ensure the continued health of marine ecosystems. Furthermore, menhaden have potential applications in aquaculture, as a source of fishmeal and fish oil, and in developing biofuels and other industrial products, offering opportunities for sustainable economic growth.

Conclusion

Menhaden are unsung heroes of marine ecosystems, providing essential ecological services such as filter feeders and forage species. A comprehensive understanding of their taxonomy, life cycle, distribution, ecological significance, and conservation status is essential to preserving these vital ecosystem engineers. As human activities continue to pose challenges to menhaden populations, it is crucial that we adopt sustainable practices to ensure the long-term health and resilience of marine ecosystems. By promoting research, conservation, and sustainable utilization of menhaden resources, we can protect their ecological role and potentially unlock new opportunities for economic growth in various industries. The future of menhaden and the ecosystems they support depends on our ability to recognize and value their importance in maintaining the delicate balance of our marine environments.