Seasonality
Each species of reef fish is unique in the frequency and timing of spawning. For some species, aggregation forming and spawning is seasonal, lasting from periods of a few to several months annually. Some species may aggregate and spawn monthly. Other patterns may exist, and for many species seasonal variability is known even across their distributional range. Variability may also occur even along the same portion of reef1. For example, in Palau, individual aggregations for the same species (squaretail coralgrouper) may lag behind one another by one month2. In some cases, a species may form an FSA for a few months of the year in one locale, and over every month of the year in another locale.
Abundance of cubera snapper (Lutjanus cyanopterus) in relation to lunar phase (circle=full moon) and seawater temperature (line) at Gladden Spit, Belize. From Heyman et al. 2005
FSA formation and spawning is usually synchronized around a specific lunar phase, for example, the full or new moons, although actual spawning may be before or after these periods. Similar to the timing of spawning, the lunar periodicity of spawning may vary for individual species among locales,3 and both the arrival and spawning of individuals may be influenced by a combination of astronomical and lunar events.
Recommended sources of information on FSA seasons include:
- Studies of historical landings and/or market or export records4
- Published studies of spawning patterns for individual species5
- Fisher interviews6
- Market surveys and fish landings7
- Direct underwater observation of FSAs8
Resources
Some of the sources listed above are available in PDF format on SCRFA's website.
1 Hamilton and Kama 2004
2 Johannes et al., 1999
3 Starr et al. 2007, Rhodes and Sadovy 2002
4 Graham et al. 2008
5 Heyman et al. 2005
6 Hamilton et al. 2005
7 Rhodes et al. 2008
8 Whaylen et al. 2004