List Data not persisting after being added in Start()

Hello all, I appologize, as this is likely a dumb question, but I am not used to using generic lists. I am trying to make a script that will control all of the enemy spawners in my scene. I need to hold the spawners in a genaric list, so that I can randomly select several of them(using the shuffle technique) and spawn enemies at them. the problem is that after finding and adding all the spawners and upon exiting the Start() function the list erases it self and is empty. I have read in several places that I need to serialize the list, but None have explained how to do this. My code is as follows

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;

 public class VRZ_SpawnController : MonoBehaviour {
 
     private List<GameObject> SpawnList;
     private int wave;
     private int spawners;
     private int totalEnemies;
     private int liveEnemies;
     private int groupSize;

     public float initialStartDelay;
     public int waves;
     public int maxSpawnsPerWave;
     public int maxSpawns;
     public int maxGroupSize;
     public float maxSpawnDelay;
     public bool allowPrioritySpawn;
     // Use this for initialization
     void Start () {
         spawners = transform.childCount;
         List<GameObject> SpawnList = new List<GameObject>();
         print(SpawnList.Count + "@1");
         for (int i = 0; i < spawners; i++) //finds all the child spawners and adds them to the list, this part works fine
         {
             SpawnList.Add(transform.FindChild("Spawn (" + i + ")").gameObject);
         }
         print(SpawnList.Count + "@2");
         StartCoroutine("Controller", initialStartDelay); //begins the spawning coroutine

     }
     int ZCount() // This counts total enemies alive, and is also working fine
     {
         print(SpawnList.Count + "@4");
         int go = 0;
         GameObject[] gos;
         gos = GameObject.FindGameObjectsWithTag("Enemy");
         go = gos.Length;
         liveEnemies = go;
         return go;
     }
     private IEnumerator Controller()
     {
         while(true)
         {
             print(SpawnList.Count + "@3");
             ZCount();
             if (liveEnemies < maxSpawns && totalEnemies < maxSpawnsPerWave) // checks is too many enemies are spawned
             {
                 print(SpawnList.Count + "@5");
                 int activeSpawners = Random.Range(0, SpawnList.Count);
                 List<GameObject> Temp = new List<GameObject>();
                 Temp = SpawnList;
                 for (int i = 0; i < activeSpawners; i++)
                 {
                     groupSize = Random.Range(1, maxGroupSize);
                     int pos = Random.Range(0, Temp.Count);
                     Temp[pos].GetComponent<VRZ_Spawn>().Spawn(groupSize);
                     Temp.RemoveAt(pos);
                 }
             }
             yield return new WaitForSeconds(10);
         }
     }
 }

Only the print(SpawnList.Count + "@2"); shows that there is anything in the list, but all print statements are reached. I just can't seem to figure out why the list clears itself after the start function

Thanks in advance for the help!