Many diverse fish species reproduce through spawning aggregations. Most involve marine fishes, including warm-water reef species like snapper and grouper, as well as valuable cold-water species like Atlantic cod. Over 200 marine fish species from more than 40 families form resident or transient spawning aggregations at specific times and locations (Rosemond et al., 2022). Major global fisheries species, such as pollock, cod, capelin, Atlantic mackerel, pilchard, and herring, also spawn this way (FAO, 2014; Sadovy de Mitcheson, 2016). According to SCRFA (2024), over 100 reef fish species, including many groupers, snappers, porgies, surgeonfish, rabbitfish, parrotfish, mullets, and wrasses, aggregate to spawn, highlighting the need for management to sustain these species and their fisheries.

   – [FAO] Food and Agriculture Organization of the UN. 2014. www.fao.org/3/a-i3720e.pdf

   – Rosemond et al., 2022. Frontiers in Marine Science. https://doi.org/10.3389/fmars.2022.931409

   – Sadovy de Mitcheson, 2016. BioScience. https://academic.oup.com/bioscience/article/66/4/295/2464056

   – SCRFA website. May 2024. https://www.scrfa.org/aggregations/what-are-aggregations/

Hundreds of thousands of fishers benefit from spawning aggregations worldwide. These fisheries are crucial at local, regional, national, and global scales, including species such as pollock, cod, mackerel, sardines, herrings, and reef fishes. The benefits extend to artisanal, recreational, and commercial fishers, and involve complex supply chains including dock and fish-house workers, retailers, and others.

Overfishing spawning aggregations can severely disrupt fish populations, as seen with the Nassau Grouper, once an abundant species. Uncontrolled fishing of large, fecund individuals significantly reduces the spawning stock, leading to the collapse of productive spawning aggregations at local and potentially regional scales. This unsustainable practice harms the fishery and the broader ecosystem.

The importance of a single aggregation to its local fish population is significant. Aggregation sites often concentrate on migratory spawners from broad areas, making them vital for local population sustainability. Unmanaged aggregation fishing reduces the spawning stock, decreasing the production of eggs and larvae and thus the number of juveniles and adults. Single aggregations can be essential for local populations, especially if there are few larvae from other sources to replenish them.

Effective conservation strategies often involve multiple layers of protection, including catch limits, seasonal limits, and spatial limits (MPAs). The best approach can vary by case. For example, a seasonal MPA may protect a site but not the migratory paths to it, where a seasonal closure could enhance protection. Establishing trust and buy-in from local fishers is crucial for compliance and effective management.

Spawning aggregations need more protection now due to increased human population and advanced fishing technology. The global population has surged from 1 billion in 1800 to over 8 billion today, greatly increasing protein demand and fishing pressures. Technological advances have made fishing far more efficient, affecting all aspects of the process. Protection is essential to prevent further losses of these keystone components of ecosystems and human nutrition.

Typically, no. Information on spawning is limited, even for well-known species like snappers and groupers. However, available data suggests that most species forming spawning aggregations do not reproduce at other places or times.