Alloparental2

Safeguarding their future: Alloparental care in Clownfishes

Binu Varghese - Marine Products Exports Development Authority, Kochi, India

Parental care in clownfishes is well known, mouthing and fanning are the important behaviours apart from
defending eggs from predators. They fan the egg mass using pectoral and caudal fins and thus provide necessary water
movement to the densely packed clutch and thus help in faster removal of metabolic wastes (Figure 1). Clownfishes also
remove unfertilized and unhealthy eggs from the clutch (egg batch). The care is mostly done by male, and on the day of
hatching eggs were vigorously fanned after sunset which helps larva to break open the thick walled egg capsule. This activity
also make sure that the hatching is complete, which is not the case in artificial incubation.

The description given above is the normal parental care behaviors in clownfishes. However, the alloparental care i.e., care
given to nondescendant egg or young one is rarely observed in fishes. In a study using true sebae Amphiprion sebae
selected from the earlier broodstock nutrition experiment, where different feeds were used to find its influence on the egg
and larval quality. Two clutches spawned on the same day with distinctly different pigmentation were used (Table 1 and Figure 2).

The pairs fed deep-sea prawn gave pinkish red eggs and theformulated diet imparted yellowish colour to eggs. The egg colour
typically reflects the dietary pigment and the initial colour of egg remains only for first two days and later it turns dark with
the embryo development. On the day of spawning the clutches were allowed to be with original parents and on the second day
noon the clutches were interchanged.

Figure 1: Parental care in sebae clownfish

Figure 2: Sebae clownfish eggs on the PVC stand pipe

Parent tank	BST IV	BST VI
Feed given	Formulated diet	Deep sea prawn
Date of spawning	20 Dec 2003	20 Dec 2003
Time of spawning	11:00 to 12:30	12:00 to 13:00
Spawning substrate	PVC airlift pipe	PVC airlift pipe
Colour of eggs	Pale yellowish	Pinkish red
Date of hatching	27 Dec 2003	27 Dec 2003

Table 1: Alloparental care experiment

After interchanging the PVC pipes with clutch the fishes were observed for their behaviour. After few minutes the male partner came to inspect the clutch from distance and returned immediately without fanning. There was no activity for a while, after about half an
hour he came close to the clutch and retreated. This continued for a while and after this initial hesitation surprisingly the pair accepted the clutch. The pairs cared for the clutch as normal and the clutches hatched completely and the larvae were also found normal and
healthy.

This behaviour might be an adaptation to ensure the survival of species governed by their social instincts. As the clown parents care for their eggs continuously it’s difficult to assume that the fishes were unaware of the change. Moreover the egg colour itself was continuing for the past six consecutive spawnings i.e. more than two months. This may be the case in nature also where the threats from predators and lose to either or both the parents are high. Step fathering in clownfishes were observed in natural habitat which owes greatly to their tight social hierarchies. More studies are required to bring insights into the amazing behaviours in these beautiful fishes.

Suggested reading

Binu Varghese (2004). Nutritional studies on the sebae anemonefish, Amphiprion sebae Bleeker 1853, with special reference to protein and lipid requirements. Thesis submitted to CIFE/ICAR, Mumbai, India.
Brian D. Wisenden (1999). Alloparental care in fishes, Reviews in Fish Biology and Fisheries 9: 45-70.

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