413
12 Species Case Studies
Bermuda (Luckhurst 1998 ; Burnett-Herkes 1975 ) and Saba, Netherland Antilles
(Kadison et al. 2009 ) and have been reported from the British Virgin Islands
(Munro and Blok 2003 ; Eristhee et al. 2006 ) and Jamaica (Munro et al. 1973 ) .
Information on the spatial structure of red hind aggregations indicates that they
consist of small haremic groups with one male defending three to fi ve females
and spawning occurs in pairs 1–2 m above the reef (Shapiro et al. 1993 ) . Sadovy
et al. ( 1994 ) suggest that red hints females are determinate spawners and spawn
more than once during the course of the annual spawning season. Red hind ovaries can be 15% of body weight (gonado-somatic index or GSI) just before
spawning (Kadison et al. 2009 ) . Fecundity can range from ca. 100,000 eggs for
a 31 cm female to ca. 1,500,000 eggs for a 41 cm female (Thompson and Munro
1978 ; Olsen and LaPlace 1979 ; Sadovy 1993a, b ; Whiteman et al. 2005 )
(Fig. 12.3a, b ). The spawning aggregation can consist of a few 100 to over 80,000
adults which occupy an area of 0.015–0.35 km
2 (Shapiro 1987 ; Shapiro et al.
1993 ; Nemeth 2005 ) . Aggregation sites typically occur on the top of deep coral
reef ridges which are located on or near the shelf edge (Colin et al. 1987 ; Beets
and Friedlander 1999 ; Nemeth 2005 ) . These locations may have specifi c oceanic
conditions that facilitate larval retention on the island shelf (Nemeth et al. 2008 ;
Cherubin et al. 2011 ) .
In the Caribbean, red hind aggregations typically form the week before the full
moon in the months of December, January and February (Shapiro et al. 1993 ; Beets
and Friedlander 1999 ; Nemeth 2005 ) . Depending upon the timing of the full moon,
red hind in the Virgin Islands begin to arrive at spawning aggregation sites after mid
December, show a distinctive peak in January about 20–40 day after the winter
solstice and disperse by the end of February (Nemeth et al. 2007 ) . Spawning typically occurs during periods of declining seawater temperature and slacking currents
within a temperature range of 26–27.5°C and current speed of 2.5–3.5 cm s
−1
. In
more northern areas (i.e. Bermuda), the spawning season occurs May through July
within the same temperature range but during periods of increasing water temperatures (Luckhurst 1998 ) . At the aggregation sites, males defend territories and display a characteristic barred colouration in the postero-ventral area; the lips also
become barred; females just before spawning exhibit highly distended abdomens
(Fig. 12.4a, b ).
Red hind migrate 5–33 km from home sites to spawning grounds at swim speeds
of 3–25 km day
−1 and encompass a catchment area of 90–500 km
2 (Sadovy et al.
1992 ; Luckhurst 1998 ; Nemeth et al. 2007 ) . Males arrive several weeks early at
spawning sites and stay for the duration of the spawning season whereas females
may only spawn during 1 month. Gender-specifi c movements during the week of
spawning cause daily fl uctuations in female:male sex ratios at the aggregation site
that range from more than 20:1 to less than 1:1. Whiteman et al. ( 2005 ) developed
the use of ultrasound imaging to determine gender non-invasively. In between
monthly spawning peaks, about 5–20% of the spawning population remain on
the aggregation site comprising the largest males and females within the aggregation
(Nemeth et al. 2007 ) .
12 Species Case Studies
Bermuda (Luckhurst 1998 ; Burnett-Herkes 1975 ) and Saba, Netherland Antilles
(Kadison et al. 2009 ) and have been reported from the British Virgin Islands
(Munro and Blok 2003 ; Eristhee et al. 2006 ) and Jamaica (Munro et al. 1973 ) .
Information on the spatial structure of red hind aggregations indicates that they
consist of small haremic groups with one male defending three to fi ve females
and spawning occurs in pairs 1–2 m above the reef (Shapiro et al. 1993 ) . Sadovy
et al. ( 1994 ) suggest that red hints females are determinate spawners and spawn
more than once during the course of the annual spawning season. Red hind ovaries can be 15% of body weight (gonado-somatic index or GSI) just before
spawning (Kadison et al. 2009 ) . Fecundity can range from ca. 100,000 eggs for
a 31 cm female to ca. 1,500,000 eggs for a 41 cm female (Thompson and Munro
1978 ; Olsen and LaPlace 1979 ; Sadovy 1993a, b ; Whiteman et al. 2005 )
(Fig. 12.3a, b ). The spawning aggregation can consist of a few 100 to over 80,000
adults which occupy an area of 0.015–0.35 km
2 (Shapiro 1987 ; Shapiro et al.
1993 ; Nemeth 2005 ) . Aggregation sites typically occur on the top of deep coral
reef ridges which are located on or near the shelf edge (Colin et al. 1987 ; Beets
and Friedlander 1999 ; Nemeth 2005 ) . These locations may have specifi c oceanic
conditions that facilitate larval retention on the island shelf (Nemeth et al. 2008 ;
Cherubin et al. 2011 ) .
In the Caribbean, red hind aggregations typically form the week before the full
moon in the months of December, January and February (Shapiro et al. 1993 ; Beets
and Friedlander 1999 ; Nemeth 2005 ) . Depending upon the timing of the full moon,
red hind in the Virgin Islands begin to arrive at spawning aggregation sites after mid
December, show a distinctive peak in January about 20–40 day after the winter
solstice and disperse by the end of February (Nemeth et al. 2007 ) . Spawning typically occurs during periods of declining seawater temperature and slacking currents
within a temperature range of 26–27.5°C and current speed of 2.5–3.5 cm s
−1
. In
more northern areas (i.e. Bermuda), the spawning season occurs May through July
within the same temperature range but during periods of increasing water temperatures (Luckhurst 1998 ) . At the aggregation sites, males defend territories and display a characteristic barred colouration in the postero-ventral area; the lips also
become barred; females just before spawning exhibit highly distended abdomens
(Fig. 12.4a, b ).
Red hind migrate 5–33 km from home sites to spawning grounds at swim speeds
of 3–25 km day
−1 and encompass a catchment area of 90–500 km
2 (Sadovy et al.
1992 ; Luckhurst 1998 ; Nemeth et al. 2007 ) . Males arrive several weeks early at
spawning sites and stay for the duration of the spawning season whereas females
may only spawn during 1 month. Gender-specifi c movements during the week of
spawning cause daily fl uctuations in female:male sex ratios at the aggregation site
that range from more than 20:1 to less than 1:1. Whiteman et al. ( 2005 ) developed
the use of ultrasound imaging to determine gender non-invasively. In between
monthly spawning peaks, about 5–20% of the spawning population remain on
the aggregation site comprising the largest males and females within the aggregation
(Nemeth et al. 2007 ) .