1 00:00:12,880 --> 00:00:16,720 Gender change can still cause a lot of discussion among people. 2 00:00:16,720 --> 00:00:20,400 In nature, however, it is a natural process 3 00:00:20,400 --> 00:00:22,520 not uncommon on coral reefs. 4 00:00:22,520 --> 00:00:26,760 In this episode you will meet a fish that is probably known to every child. 5 00:00:29,120 --> 00:00:31,240 But from a slightly different side. 6 00:00:31,320 --> 00:00:34,920 Sex is established relatively early in most vertebrates 7 00:00:34,920 --> 00:00:37,120 and it doesn't change anymore. 8 00:00:37,160 --> 00:00:39,240 However, some bony fish 9 00:00:39,240 --> 00:00:42,240 they can surprise us. 10 00:00:42,440 --> 00:00:43,160 Why? 11 00:00:43,200 --> 00:00:46,000 Because they have the ability to change sex 12 00:00:46,400 --> 00:00:50,360 in adulthood under the influence of environmental factors. 13 00:00:50,520 --> 00:00:54,880 A species of fish that is an iconic example of sex change 14 00:00:54,880 --> 00:00:59,320 is your favorite, in the world of children known as "Nemo". 15 00:01:02,600 --> 00:01:05,160 i.e. clownfish. 16 00:01:05,320 --> 00:01:08,160 Notice that little Nemo is a boy. 17 00:01:08,160 --> 00:01:11,520 This has some justification in reality. 18 00:01:11,520 --> 00:01:16,240 In clownfish, we can observe the phenomenon of the so-called protandry. 19 00:01:16,240 --> 00:01:20,520 This is the earlier maturation of the male gonads. 20 00:01:20,520 --> 00:01:24,360 In short, this means that our clownfish mature as "boys". 21 00:01:26,720 --> 00:01:29,480 Clownfish are monogamous fish. 22 00:01:29,480 --> 00:01:31,160 They have one partner. 23 00:01:31,160 --> 00:01:34,160 They can live in pairs or groups. 24 00:01:34,240 --> 00:01:36,520 There is a hierarchy in this group. 25 00:01:36,520 --> 00:01:38,840 The largest individual is the female, 26 00:01:38,840 --> 00:01:41,000 accompanied by a mature male 27 00:01:41,000 --> 00:01:42,440 and young males. 28 00:01:42,440 --> 00:01:45,120 But what happens if our female gets lost somewhere? 29 00:01:45,120 --> 00:01:48,320 The dominant male "breeder" changes sex 30 00:01:48,360 --> 00:01:50,280 and takes the place of the female. 31 00:01:50,280 --> 00:01:57,000 And the dominant "male" matures, becomes a "breeding" male. 32 00:01:57,000 --> 00:02:00,960 Such a system of offspring production and the social structure of clownfish 33 00:02:00,960 --> 00:02:06,400 is largely dependent on the presence of sea anemones in their environment. 34 00:02:06,480 --> 00:02:09,720 Some sea anemones can reach enormous sizes. 35 00:02:09,800 --> 00:02:12,080 They are the home of our clownfish, 36 00:02:12,080 --> 00:02:20,560 where they can find shelter from predators, lay their eggs in a safe place and get food. 37 00:02:20,560 --> 00:02:25,320 However, sea anemones on coral reefs can be distributed in a variety of ways. 38 00:02:25,320 --> 00:02:27,520 Some are relatively far apart. 39 00:02:27,520 --> 00:02:33,120 This means that for our clownfish, changing the host may carry a deadly risk. 40 00:02:37,640 --> 00:02:42,680 So a gender reassignment strategy protects them from taking that risk. 41 00:02:42,720 --> 00:02:46,720 However, this reproductive strategy requires a lot of time and energy. 42 00:02:46,720 --> 00:02:52,000 Sex change in such a clownfish can take a long time, and during this time they do not reproduce. 43 00:02:52,000 --> 00:02:54,680 So it's kind of a waste of time. 44 00:02:55,840 --> 00:03:01,600 Interestingly, in places where we have more sea anemones, such hierarchical ties are more loose. 45 00:03:01,760 --> 00:03:08,360 It is a safe environment and males migrate more often in search of a new partner. 46 00:03:08,560 --> 00:03:13,880 If we were to define the "social system" chosen by clownfish, it is naturally "matriarchy", 47 00:03:14,000 --> 00:03:16,400 where women are in power. 48 00:03:17,520 --> 00:03:23,640 The female, being bigger, stronger, more aggressive, patrols her territory. 49 00:03:23,640 --> 00:03:25,800 “The woman beats me...” 50 00:03:25,880 --> 00:03:30,480 In contrast, all males in the group care for the offspring, 51 00:03:30,560 --> 00:03:35,720 thus contributing to the reproductive success of the main pair. 52 00:03:35,720 --> 00:03:38,720 In the Gdynia Aquarium we breed three species of clownfish. 53 00:03:38,840 --> 00:03:42,360 The simplest in breeding is naturally our clownfish. 54 00:03:42,760 --> 00:03:47,120 The older the pair of clownfish, the more eggs they can lay. 55 00:03:47,120 --> 00:03:51,840 Spawn in breeding tanks is laid by a couple more or less every month. 56 00:03:51,840 --> 00:03:55,840 Such pairs can lay 100-200 eggs at a time. 57 00:03:55,840 --> 00:04:03,760 They lay their eggs on hard surfaces. Aquarists use, for example, pots or - as in our case - PVC pipes. 58 00:04:03,760 --> 00:04:08,560 After 8-9 days, small larvae hatch from the eggs. 59 00:04:08,560 --> 00:04:10,160 This usually happens at night. 60 00:04:10,200 --> 00:04:12,880 The young are placed in a dense plankton suspension 61 00:04:12,880 --> 00:04:16,760 composed of small plant and animal organisms, 62 00:04:16,760 --> 00:04:19,760 so that they have enough food. 63 00:04:19,920 --> 00:04:23,720 After a week, they develop an appetite for small crustaceans. 64 00:04:23,720 --> 00:04:28,200 After 3 months, they are already about 3-4 cm long. 65 00:04:28,200 --> 00:04:31,840 So you see - our clownfish can surprise. 66 00:04:31,840 --> 00:04:39,800 I hope that after this episode, coral reefs will be an example of a wonderful, colorful ecosystem for you, 67 00:04:39,800 --> 00:04:43,400 where the rules of life can change, 68 00:04:43,400 --> 00:04:45,960 sometimes contrary to our expectations.